Pruning Trees and Shrubs

Pruning Trees and Shrubs

Brian Jervis: Ask A Master Gardener

Sunday, December 22, 2019

Q: I need to do some trimming and pruning on our trees and shrubs. Is now a good time to do that? MA

A: Pruning and trimming is an important part of keeping our trees and shrubs healthy as long as you know when to prune and how. It can also be a little tricky because now is the perfect time for some plants and not so great for others. Here are some general tips to help.

We prune for a variety of reasons: training and shaping the plant, thinning for better air circulation and health, removal of dead branches, stimulating new growth or flowers, or to keep plants away from our homes or other structures.

One thing to remember is to never remove more than about a third of the branches. If you do a good job pruning, your work will not be noticeable. It will look natural and not like you were trimming with a vengeance. This un-natural manner of trimming can be seen all over town in what we gardeners call “crape murder” (the over-aggressive trimming of crape myrtles you see in the photo and all over town).

Here are some general rules on when to prune.

Flowering trees, shrubs and vines typically should not be pruned in the winter as many of these set the flower buds for the next year in the summer. Most hydrangeas fall into this category (except the Oak Leaf variety). If you have not been getting flowers on your hydrangeas, have you been cutting back those dead-looking stems in the fall or winter? They can be a little unsightly, but the best time to prune these is after their blooming burst in the spring so they will have time to set buds for the following year. Other shrubs that fall into this category are flowering quince, forsythia, viburnum and wisteria.

Another group is the summer-flowering varieties, such as abelia, butterfly bush or Rose of Sharon. These should be pruned in the fall or early spring.

There is also a category of broadleaf evergreen plants like acuba, camellia, boxwood, cherry laurel, holly, mahonia, nandina and photinia. These are best pruned in the spring before new growth begins.

Tree trimming and pruning is typically best left to trained professionals. I know, a lot of us consider ourselves chain-saw warriors, but there is a difference between cutting up a branch that fell to the ground and successfully cutting that several hundred-pound branch off a tree. Typically, this type of work is better left in the hands of a trained arborist. Tulsa is fortunate to have several arborists to from which to choose. To find a good arborist, we suggest you visit treesaregood.org. This is the national database of arborists. Their website will help you find a local licensed arborist who will meet your needs.

We have an extensive list of different varieties of how to trim on our website. We also have a video on how to plants that include recommendations on when and properly trim crape myrtles. You can find this and more information on our website, tulsamastergardeners.org, by clicking the “Hot Topics” button on the home page. Good luck and stay safe.

Garden tips

·        All birds need and appreciate clean feeders and unfrozen water on cold days. Place feeders close to protective shelter, if possible.

·        Be sure to keep your Christmas tree watered to keep if from drying out.

·        Light prunings of evergreens can be used for holiday decorations. Be careful with sap that can mar surfaces.

·        Newly seeded fescue will continue to grow roots and make energy if you keep them free of leaves.

Poinsettia Care

Poinsettias: How to Achieve Re-Flowering Next Season

Tom Ingram: Ask A Master Gardener

Sunday, December 8, 2019

Q: Each year I purchase a new poinsettia and each year I end up throwing it away. Is there a way to keep it until next year? CH

A: Poinsettias are our favorite Christmas plant with sales of over $250 million dollars each year. That’s a lot of poinsettias!

Poinsettias are the namesake of Joel Poinsett, the first U.S. Ambassador to Mexico, who first brought these plants north to the United States. In their native Mexico, they are a perennial and can grow 10 to 15 feet tall making a beautiful shrub. In honor of Poinsett, Dec. 15 is National Poinsettia Day which coincides with the death of Poinsett in 1851.

Believe it or not, the poinsettia has also been known by several names; such as the Lobster Flower or the Flame-Leaf Flower due to the red color of its bracts (that is what those red leaves are called). But good luck walking into your local nursery and asking where the Lobster Flowers are. OK, so enough with the history lesson, let’s get back to the question.

As gardeners we hate to just throw away a potential new member of our garden tribe, but some plants kind of nudge us to move in that direction. If you want to try and keep your poinsettia alive while encouraging it to develop those beautiful red bracts next year, here is what you are going to need to do.

1) At the first of the year you should fertilize your poinsettia with a good all-purpose fertilizer and provide it with adequate sun and water indoors.

2) Sometimes the plants can become leggy, so around mid-February, trim it back to around 5” in total height.

3) Mid-March remove the dried and faded parts of the plant.

4) Mid-May (after the danger of a freeze is over), you can move the plant outside to a place that gets indirect sunlight. Keep them away from locations that get hot-drying winds. Trim the longer branches back about 2 or 3 inches to shape the plant into a rounded bushy plant. Be prepared to replant if it outgrows its container. Continue to water and apply a house plant fertilizer at the recommended rate.

5) In late September, bring the plant indoors and place it in a sunny location. At this point the plant needs to rotate between absolute darkness and sunlight to begin developing that bright red color. To accomplish this, leave them in the sunny location each day, but place them in absolute darkness from 5 p.m. each evening and leave them there till about 8 a.m. Follow this daily procedure daily for about two months and you should you get good red bract color, typically by Thanksgiving.

Or, you could do what most of us do; enjoy them while we have them and purchase a new one each year.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th St., or by emailing us at mg@tulsamastergardeners.org.

Garden tips

• Apply dormant oil for scale infested trees (crape myrtle bark scale) and shrubs when temperatures are above 40 degrees.

• If your roses have not been mulched, do so now. This is a good place to use those fall leaves which have been shredded with a mulching mower. Mulch not only will prevent cold damage to those plants which are susceptible but will prevent warming of soil on warm winter days which may promote premature cold sensitive new growth

Proper Mulching Around Trees

Avoid “Volcano” Mulch Around Trees

Brian Jervis: Ask A Master Gardener

Sunday, November 24, 2019

Q: As I drive around town, I see small trees and crape myrtles with very large mounds of mulch, kind of like a pyramid. Is that the right way to do it? VM

A: Master Gardeners call that a “volcano” of mulch and the No. 1 rule in the mulching handbook says, “just say no to the volcano.” More on the volcano later.

In reality, mulching your plants, trees, and shrubs (properly), is one of the best things you can do to contribute to their long-term success. Here’s why:

Mulch greatly diminishes the quantity of weeds. The protective barrier that mulch provides not only stops migrating weed seeds from making contact with the soil to take root, but also provides a barrier that diminishes the ability of emerging weeds to grow. Fewer weeds means more nutrients and water available for your plants. A good layer of mulch also reduces the time you need to spend on your knees pulling weeds.

Mulch helps regulate soil temperature. During the height of summer, exposed soil here in Oklahoma can vary by up to 40 degrees in a single day, with soil temperatures reaching almost 120 degrees at a 1” depth. When you use mulch, that daily temperature variant is reduced to only about 10 degrees. This provides a much healthier growing environment for your plants.

Mulch helps with water management. As you might imagine with the extreme soil temperatures of un-mulched soil, water management easily becomes a challenge. High soil temps cause the water to evaporate quickly. This increases the need for water, which directly corresponds to the amount of time you need to spend watering. In addition, more time watering typically equates to an increase in your monthly water bill.

Even in the winter, mulch can help retain moisture and protect your plants from cold winter extremes, decreasing the chances of those tender perennials freezing out.

There are a variety of mulch types you can use in your garden: wood chips, sawdust, straw, and even mulched leaves. As we are in the season where the leaves are falling or have already fallen, mulched leaves make a great garden mulch. You can run your leaves through a relatively inexpensive leaf mulcher or pile them in the driveway and let your lawn mower do the work.

After mulching, just bag them up, store them in an out-of-the-way place and next spring you will have your garden mulch ready to go. This also helps add organic matter back into the soil; something most every garden in NE Oklahoma will appreciate.

Now, back to the volcano. The main problem with mulch volcanos is that they are piled up around the trunk of the shrub or tree. As we have mentioned, mulch helps retain moisture and piling mulch against the trunks helps keep them moist, which contributes to disease and bark degradation … ultimately shortening the life of these plants. Mulching around trees and shrubs is great, just keep the mulch a few inches away from their trunks.

Remember, just say no to the mulch volcano!

Garden tips

·        Apply dormant oil for scale infested trees and shrubs before temperatures fall below 40 degrees Fahrenheit. This would include crape myrtles infected with crape myrtle bark scale. Follow label directions.

·        Continue to plant balled and burlapped trees.

·        Wrap young, thin-barked trees with a commercial protective material to prevent southwest tree injury.

Southwest Injury to Tree Bark

Southwest Injury to Tree Bark

Tom Ingram: Ask a Master Gardener

Sunday, November 10, 2019

Q: I planted a maple tree a few years ago and now the bark is split. What should I do? EH

A: The damage you are describing is likely what we call Southwest Tree Injury. It’s not called that because the ailment only affects trees in the southwest part of the country, but because it is damage that appears on the southwest side of the tree.

Southwest tree injury occurs during the overwintering of thin barked, oftentimes, freshly planted young trees.

During daylight hours, the winter sun warms the bark which causes it to expand. At night, the cold chills the bark causing it to contract. As this process repeats each day, the bark can be damaged, resulting in a split in the bark. Most trees do not recover from this damage.

You can see trees with this problem all around town, especially in new construction or in parking lots. New young trees are planted in small areas of the parking lot. The heating and cooling of the bark in winter is exaggerated because the tree is typically surrounded by asphalt causing more heat to be generated and reflected onto the bark of the young tree. Southwest tree injury is very common in these situations. The next time you are driving through one of these lots, look at the trees. If they are thin barked trees, they likely will have southwest tree injury.

Certain trees are more susceptible such as cherry, maple, weeping willow, and various fruit trees. However, this problem can be mitigated with a simple strategy.

As we enter the winter season, wrap the trunks of any newly planted thin-barked trees with paper tree wrap. This wrap should not be tight as you want circulation, but you also want it snug enough to remain in place. In the spring, as it begins to warm up, remove the tape. This process should be repeated for at least the first two or three years. After that, the bark should be strong enough to remain unaffected by the changing temperature. Most garden centers should carry this tree wrap.

Once the damage has occurred, there is not much you can do. The tree will try to heal the gap but is rarely successful due to the size of the damage. These gaps will make the tree more vulnerable to disease as the inner layers of the tree are exposed. But the good news is that you can avoid southwest tree injury with a little effort and a roll of inexpensive paper tree wrap.

Garden tips

-         Remove all debris from the vegetable and flower garden to prevent overwintering of various garden pests.

-         Cover water gardens with bird netting to catch dropping leaves. Take tropical water garden plants indoors and stop feeding fish when water temperatures near 50 degrees.

-         Start new garden bed preparations now. Till plenty of organic material into the soil in preparation for spring planting

Fall Planting of Bulbs and Pansies

Fall Planting

Brian Jervis: Ask A Master Gardener

Sunday, October 27, 2019

Q: Winter is so dreary for us gardeners. Any suggestions for something to lift my spirits? CH

A: You are right to some degree. After all the anticipation of spring: the planning, the planting, the waiting, and the fighting off the predators who seem determined to destroy our beauties, many gardeners find themselves with nothing left but memories this time of year. But here are a couple of things you can do to keep your gardener blood pumping through the coming winter.

Pansies

If you have never planted pansies you are missing out on a true winter beauty. We are fortunate in Tulsa since we have a variety of local growers who produce pansies for our local market. If you are a fan of “local,” pansies can’t be beat. They are also available in a large variety of colors: even an orange and black if you are so inclined (Go Pokes!).

Pansies require no special planting instructions, just loosen the soil, sprinkle in some garden fertilizer and plant: usually about 4-6 inches. It won’t be long before they will start to fill in with beautiful flowers.

Watering is something that can be overlooked during the winter, but your pansies, will still need to be watered from time to time depending on the conditions. With proper care, your pansies should be beautiful throughout the winter and early spring.

One of the main challenges we can experience with pansies is that they tend to really come on strong about the time we need to begin pulling them out to prep our spring garden beds. But if you don’t, you will likely miss some opportunities in the spring when the new shipments of flowers start arriving in the nurseries.

Bulbs

Planting bulbs is something else you can do now, but you’ll have to wait till spring to see the results of your efforts. We plant bulbs in the fall because they need the winter “chill” period to prepare them for spring blooming.

Tulips, gladiolas, and daffodils are great choices and come in a variety of colors. Planting bulbs is pretty simple with the depth of the planting hole depending on the height of the bulb.

First, loosen the soil, then dig a hole about 3 times the height of the bulb. Place the large end of the bulb down in the hole; sprinkle with a little fertilizer, cover, and water in. After that you can pretty much forget about them. Just remember where you planted them so when you start planting your spring flowers, they won’t get disturbed.

Then, sometime in the spring (depending on what you planted) these green shoots will start coming out of the ground alerting you to what is coming.

After they have bloomed and the flowers have disappeared, leave the leaves alone until they turn brown since they will still be helping to store nutrients for the next season.

Nothing like a little winter color and the anticipation of spring flowers to help gardeners get through the winter.

Garden Tips

- Remove green fruit from tomato plants when frost threatens. If they are green but full sized, they will ripen indoors. They do not need to be in sunshine to ripen indoors.

- Use a cold frame device to plant spinach, lettuce and various other cool-season crops for production most of the winter.

- Take tropical water garden plants indoors when the water temperature reaches 50 degrees. Also, stop feeding fish in the pond at this water temperature.

Plant Garlic in Fall, Harvest in Early Summer

Plant Garlic Now

Tom Ingram: Ask a Master Gardener

Sunday, October 13, 2019

Q: I’ve heard that fall is a good time to plant garlic. Is that correct? — MC

A: We love our garlic. Garlic is a common seasoning worldwide and it’s not hard to understand why as the smell of garlic cooking makes almost any meal seem better.

Growing your own garlic is pretty simple. First, you need to select your bulbs. It’s good to start your search early so you can find the largest and firmest bulbs for planting. OSU recommends several varieties: German Red, Spanish Roja, Inchelium Red and Silver Skin.

Now is a good time to plant your garlic. The two most important elements that you will need to consider are sun and soil. An area that receives full sun is best. And the soil needs good drainage. Loose, loamy soil will give you good drainage and allow the bulbs to expand as they grow. Before planting you may want to work an organic nitrogen-rich fertilizer into the soil such as blood meal.

Garlic grows from the individual cloves that make up the garlic bulb. You will want to select the largest outside cloves for planting. If your soil is loose enough, you should be able to just push the clove into the soil, root — or flat — end down. Plant the cloves about two inches deep with the pointy tip up. You should allow 4–6 inches between cloves for good bulb growth.

Unlike many veggies that have specific space requirements, garlic takes up very little space. And it’s not a requirement that you have a veggie patch; garlic can be right at home in the flower garden. After planting, a healthy layer of mulch like straw, leaves or dry grass clippings will help maintain soil temperatures and control weeds.

The fall growing season will produce some small shoots but is primarily for root production. Bulbs will rest over the winter in preparation for a spring growth spurt. During this growth period, additional watering may be indicated if rainfall is not sufficient.

In late June or early July, leaves should start turning yellow brown, indicating it’s time to harvest. Gently dig bulbs from the ground. Bulbs will need to be cured in a dry, shaded area for 4–6 weeks. After drying, carefully remove the stalks leaving the outer skin intact. Carefully stored garlic can last up to several months and it will likely taste better since you grew it yourself!

Garden tips

• Plant container-grown trees and shrubs this month. Fall is generally the best time to plant. At this time the plants have no energy drain to produce leaves and can concentrate on growing a root system until the soil gets cool in winter. They are better prepared for spring growth if planted in the previous fall.

• Check and treat houseplants for insect pests before bringing inside. Look at the roots and repot those which are root-bound. Irrigate the soil thoroughly before bringing inside.

• There is still time to plant radishes and mustard in the fall garden.

Milkweed Tussock Moth

Milkweed Tussock Moth

Tom Ingram: Ask A Master Gardener

Sunday, September 15, 2019

Q: I grow milkweed in my garden for the migrating monarchs, but there are some fuzzy caterpillars that are black, orange and white devouring my milkweed. What are they and what should I do about them? MC

A: Monarch butterflies are often in the news. We hear about their dwindling population, and many people are planting a variety of plants to support them on their migration to and from Mexico. Milkweed is the sole source of nutrients for monarch caterpillars. However, what you are describing is another insect whose caterpillars also prefer milkweed: the milkweed tussock moth.

Female milkweed tussock moths lay their eggs in white masses on the underside of milkweed leaves starting in June. When the eggs hatch, they begin feeding and may go unnoticed for a while.

By their third instar (a phase during the developmental process), they become these unique and beautiful fuzzy caterpillars with tufts of black, orange and white. The adult moths are not nearly as stunning, but many of us have been told we were better looking when we were younger so…

If the female moth laid all her eggs in one spot, what starts as a kind of mob feeding thins out as the larger caterpillars spread out and move to other milkweed plants. At the point they are in full tufts mode, they tend to feed alone or in pairs.

Soon, they leave the milkweed plants to form a cocoon in which they pupate. Farther north, there is only one generation per year, but in our area, two generations per year are not unusual.

Bats are the primary predators of moths; however, the milkweed tussock moth tends to be immune from being fed upon by bats because they produce an ultrasonic click from what is called a tymbal organ. Bats recognize this sound and avoid them because they are not interested in a toxic meal. The moths are toxic (like monarchs) because their favorite food (milkweed) contains a poison called cardiac glycosides (cardenolides). Being toxic is a great way to get predators to leave you alone.

The caterpillars are voracious eaters and can decimate your milkweed plants, so, if found, you have a decision to make. Because you said you grow milkweed for the monarchs, you might consider the milkweed tussock moth an unwelcome interloper. Or perhaps you can just embrace the idea that you were growing caterpillar food, which is serving its intended purpose, just not in the way you had planned.

If the live-and-let-live philosophy doesn’t work for you, you will want to remove the milkweed tussock moth larvae. Physical removal would be best as any chemicals you might use could work to the detriment of your monarch sanctuary.

As for me, the photo of the milkweed tussock moth seen here is from my garden. I didn’t enjoy seeing my milkweed disappear before any monarchs found it, but I decided to enjoy and appreciate the milkweed tussock moth’s beauty while hoping they leave something for the monarchs. Maybe you will, too.

You can get answers to all your gardening questions by calling the Tulsa Master Gardeners Help Line at 918-746-3701, dropping by our Diagnostic Center at 4116 E. 15th Street, or by emailing us at mg@tulsamastergardeners.org.

Garden tips

·        Watch for fall specials at garden centers and nurseries because fall is a great time for planting many ornamentals. Choose spring-flowering bulbs as soon as available.

·        Fertilize established fescue lawns with 1 pound of actual nitrogen fertilizer per 1,000 square feet now and again in November. Do not fertilize Bermuda or zoysia lawns until next spring. Late fertilization of these warm-season grasses may promote disease.

·        September and early October is garlic-planting time with an aim for harvest in June of next year. There are many varieties from which to choose. OSU suggests German Red, Inchilium Red, Silverskin and Spanish Roja for varieties that do well in our area.

·        Remember, our Fall Lunch & Learn classes will be starting Tuesday, Sept. 17. You can find more information and topics on our website.

Fall Is The Time To Reseed Tall Fescue Lawns

Reseeding Tall Fescue Turfgrass

Brian Jervis: Ask A Master Gardener

Sunday, September 1, 2019

Q: I understand that fall is the best time to reseed with fescue. However, I am not sure how to do it and what type of seeds to buy. Can you help me? Robert T., Broken Arrow

A: Fescue is called a “cool season” turf grass for a reason. It does not tolerate hot weather well at all. We have just had a big dose of heat, and there are many brown patches in Tulsa’s fescue lawns that need reseeding. The good news is that it is about time to do so. The ideal time for sowing cool-grass lawn seed is from mid-September to mid-October. It is also generally recommended that a soil test be performed before reseeding to determine what nutrient amendments might be needed. Therefore, right now would be a perfect time to do this because there is time to get your soil test results back before time to reseed.

If weeds and/or Bermuda grass are present, spray the planting area with a glyphosate product. Two spray applications will be needed to fully eradicate Bermuda grass. One week later, the dead weeds and grass can then be raked and removed.

If the soil is compacted, it will need to be tilled (either by machine or by hand) to be receptive to the seed. A starter fertilizer, along with any amendments you might wish to use (e.g., organic compost), should be added at the time of tilling.

Read the label directions to sow the proper amount of seed to get good coverage, but avoid excess seeding. More is not better. After sowing, the top of the soil needs to be kept constantly moist (not wet) until seedlings are 2 inches tall. Then, change to less frequent and deeper watering to encourage deep roots. While there are no guarantees, this will help to improve the sustainability of fescue through the hot summer months. The grass should be mowed with a sharp-bladed mower after reaching a height of 3 inches. Another application of a nitrogen fertilizer should be made in November.

One of the common issues in reseeding cool-grass lawns is deciding what type of grass seed should be used. Unfortunately, there is not one that is bulletproof, and no one single fescue variety stands out as the best overall. Each fescue variety, individually, has its own strengths and weaknesses. Therefore, it is recommended that a mixture (two or more species) of fescue, Kentucky bluegrass and perennial rye grass be used to cope with various diseases. Another appropriate choice is to use one of several mixtures of tall fescue without the other turf grass seeds. Any of these mixtures will perform well and will be better than a single type of fescue alone.

One thing is clear — we live in a difficult area to grow cool-season grasses. Detailed instructions for lawn seeding are available in OSU Fact Sheet HLA-6419, “Establishing a Lawn in Oklahoma.”

Garden tips

• Always follow directions on the labels of synthetic and natural pesticide products. Labels will always list where the product may be used and which pest it is certified to cover. If you do spray pesticides, do it early in the morning or late in the evening after bees have returned to their colony.

• If your tomatoes are too tall and gangling, now is a good time to prune the top of the plants by as much as ⅓ to ½ depending on the plant. This will stimulate new limb growth and new fruit production after it cools.

• Tall fescue should be mowed at 3 inches and up to 3½ inches if it grows under heavier shade. Do not fertilize fescue lawns until it cools in September, then fertilize once again in November. Do not fertilize in the summer.

• Now is a good time to submit a soil sample to the OSU Extension office for testing. Do this before reseeding fescue or creating a garden bed this fall. You can call the Master Gardener office at 918-746-3701 for instructions.

How Best to Water Lawns in Summertime

How To Water Lawns in Summer

Tom Ingram: Ask A Master Gardener

Sunday, August 18, 2019

Q: It’s been so hot outside. How do I know how much I should be watering my lawn? JB

A: Keeping our growing things alive in July and August can be a challenge in Oklahoma. However, there are some general guidelines that can help.

If your lawn is primarily Bermuda (or another warm-season grass), it needs about 1 inch of water per week this time of year, while fescue (or other cool-season grasses) need about double that or 2 inches of water per week.

Whenever we tell someone this, the next question is typically something like, “Then how long do I run my sprinkler to get an inch of water?” The answer to that question necessitates you doing what we call a “simple irrigation audit.”

For a simple irrigation audit, you are going to need nine collection cups, a pen, paper and a calculator (most of us will probably need a calculator). Collection cups can typically be purchased from an irrigation supply store or you can use clean metal cans that might previously have contained tuna, cat food or perhaps tomato paste. You will get the best results if all your collection cups are the same.

If you choose cans, you can use a ruler and a fine-tip permanent marker to mark the outside of the cans in ¼-inch increments. Or you can just measure the collected water by sticking a ruler directly into each collection can.

To collect your measurements, place your nine collection cans about 8 feet apart in something close to a 16-by-16-foot grid. For best results, do this in one sprinkler zone at a time.

Next, let your sprinkler run over your collection grid for 20 minutes. After the collection period is over, measure the amount of water in each of your collection cups, add up the total amount collected (now it’s calculator time), and divide the total by nine because you were using nine collection cans. This will give you an average amount of water your collection grid area received in 20 minutes.

So let’s assume your average measured amount was ½ inch. This means for every 20 minutes your sprinkler system runs, your turf will be receiving a ½ inch of water. If you have Bermuda grass, which needs 1 inch of water per week, you are going to need to water twice that amount, or 40 minutes per week. You can split this up into two watering sessions per week of 20 minutes each.

If you have a fescue lawn, which needs 2 inches of water per week, the math says you would need 80 minutes per week, which can be split up into two watering sessions of 40 minutes each. This would not be a total for your yard, just for that zone. As you can imagine, each zone is going to be a little different, so for complete accuracy, you would need to repeat the process for each zone.

Performing this simple irrigation audit will likely end up saving you money, as most of us overestimate the water needs of our turf and end up “pouring money down the drain.”

Garden tips

·        August is a good month to start more crops in your fall vegetable garden. Bush beans, cucumbers and summer squash can be replanted for another crop. Beets, broccoli, carrots, potatoes, lettuce and other cool-season crops can also be planted at this time.

·        Discontinue deadheading roses by mid-August to help initiate winter hardiness.

·        Irrigated warm-season lawns, such as Bermuda and zoysia, can be fertilized once again; apply 1 pound nitrogen per 1,000 square feet this month. Do not fertilize these grasses after the end of August. Do not fertilize tall fescue lawns in summer; fertilize in late September after it cools and again in November.

·        Make a note on your calendar that our free Fall Lunch & Learn classes will be starting Sept. 17. You can find more information and topics on our website

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OSU Tulsa MG Training Program Enrollment Is This Month

OSU Tulsa Master Gardener Program

Brian Jervis: Ask A Master Gardener

Sunday, August 4, 2019

A: From time to time, I hear about Tulsa County Master Gardeners. Can you inform me about what they do and how to join that organization? Rhonda B., Tulsa

A: Even though the Tulsa County Master Gardeners have been around since 1983, many in the community are not familiar with our organization, mission and activities. Numbering just more than 400, these Master Gardeners are volunteer educators trained by Oklahoma State University whose mission is to provide OSU Extension research-based horticultural information to local home gardeners and the community.

Education is our primary mission. As such, you will find us around town at various venues, such as the HBA Spring Home & Garden Show, in K-5 classrooms and in senior living centers. As an example of our outreach, in 2018, we were in 87 different schools and 754 classrooms teaching a variety of science-based classes to almost 18,000 elementary school students throughout Tulsa County. Additionally, each year we host an Insect Adventure on the fairgrounds for more than 1,000 elementary school students, helping them gain a respect for the wonderful variety of insects with which we share this planet and the many benefits they provide. On the other end of the age spectrum, we were also in 30 assisted living centers interacting with about 400 seniors to provide a little horticultural therapy, which brightens their day, as well as ours.

Another way we fulfill that mission is by staffing a Horticultural Diagnostic Center at the Tulsa County OSU Extension office from 9 a.m. to 4 p.m. Monday-Friday. Here, you can find Master Gardeners on hand to answer your questions via phone, email or in person. And while there, located just outside, you will find our beautiful Master Gardener maintained Demonstration Instructional Garden (DIG) containing more than 200 annuals, perennials, shrubs and trees.

We also teach a variety of classes in the spring and fall called the “Lunch and Learn” series at the Central Library downtown, as well as yearly Urban Gardener classes at the Extension Office that include topics such as plant biology, soil chemistry, growing fruits and vegetables, lawn care, trees and shrubs, flowers and container gardening.

Other activities include providing educational booths at various festivals around town or, in May, you may have visited one of our homes on the Master Gardener Garden Tour. Partnering with Habitat for Humanity, we make sure these new homeowners don’t just get a house but also a beautifully landscaped yard. In an effort to help beautify Tulsa, the Master Gardeners spend hours planting and maintaining beautiful flowers in planters along Brookside and in the Blue Dome district.

So now that you know what a Tulsa Master Gardener does, are you interested in becoming one yourself? At 1 p.m. Aug. 7 and 10 a.m. Aug. 14, you may attend a presentation at the OSU Extension Office (4116 E. 15th St.) where you can learn about the requirements to become a Tulsa Master Gardener and fill out an application. This enrollment only occurs once a year, so if you have an interest, be sure to attend one of these presentations.

Garden tips

• Water all plants deeply and early in the morning. Most plants need approximately 1 to 2 inches of water per week. Rather than watering daily, water less often and more deeply.

• Fertilization of warm-season grasses can continue if water is present for growth. Do not fertilize Bermuda or zoysia lawns after the end of August. Do not fertilize fescue lawns until it cools off in late September.

• Establishment of warm-season grasses, such as Bermuda and Zoysia, by sodding or sprigging should be completed by the end of July to ensure the least risk of winter kill.

• Mowing heights for cool-season turf grasses should be at 3 inches during hot, dry summer months. Gradually raise mowing height of Bermuda grass lawns from 1½ to 2 inches.

• Cucumbers may be bitter this time of year and vines quit producing. This is due to the heat. If you are able to get the vines through the summer, they will be fertile again after it cools, and the taste of the cucumbers will improve.

Now Is The Time To Start A Fall Vegetable Garden

Fall Vegetable Gardening

Tom Ingram: Ask A Master Gardener

Sunday, July 21, 2019

Q: Our weather was so wet this spring, my vegetable garden never really took off. I was thinking of starting a fall garden. What vegetables can I grow in the fall? BD

A: We feel your pain. Due to our wet spring, just about the time tomatoes started doing well, many gardeners started getting blossom drop. Blossom drop occurs when the nighttime temperatures are above 70 degrees and the daytime temperatures are consistently above 92 degrees. When this happens, the best plan is to help your tomato plants survive the summer so that they can begin to fruit again when the weather cools down. There is no need to pull them out and start with new plants, unless you have some disease issues going on and want a fresh start or to try a different variety.

What many people do not realize is that some of the best and tastiest vegetables are grown in the fall when warm, sunny days and cool, humid nights create wonderful growing conditions.

Fall crops can be divided into two groups: tender and semi-hardy. Tender means these vegetables will need to reach full maturity and production before the first frost bring their season to an end. Semi-hardy means these plants will continue to grow and have harvestable fruits until after several frosts.

In northeast Oklahoma, Nov. 15 is our average first freeze date. So, unless something unusual happens (in Oklahoma?), you can have fresh vegetables straight from the vine until November and then refrigerate the rest for continued enjoyment.

Good tender varieties you could plant now include bush beans, lima beans, cucumber and squash. Semi-hardy crops include cabbage and cauliflower (transplants), collards, potatoes (seed potatoes), kale, kohlrabi, lettuce, parsnips, radish, swiss chard and turnips.

Beginning in September, you can plant garlic and onions, which are great crops to start in the fall, as they grow all winter. If you do this, in late spring next year, you can harvest fresh garlic and onions to last you the entire year (if you grew enough).

Whether you have a summer or fall garden, mulch should be an important part of your garden strategy, as it helps retain moisture, as well as reduces the need for weeding. In addition, mulch helps control soil temperature swings during the day. The soil temperature of un-mulched soil can vary up to 30 degrees per day with mulch reducing that to 10-15 degrees per day. Your plants will be happier and will perform better with mulch. In addition, mulch can provide a barrier for soil-borne diseases, such as septoria leaf spot in tomatoes.

If your spring and summer garden struggled or you just want to keep the harvest going, fall gardens are a great choice.

Garden tips

·        Divide and replant crowded hybrid iris (bearded iris) after flowering until August. When planting, take care not to plant the rhizomes too deeply. Cover them with an inch of soil or less. Do not mulch iris.

·        Water all plants deeply and early in the morning. Most plants need approximately 1 to 2 inches of water per week. Rather than watering daily, water less often and more deeply.

·        Some trees, such as sycamores and river birches, lose large numbers of leaves in the heat of summer. Trees do this to reduce water loss from their leaves. It is a coping action by the tree; it is not dying.

·        Master Gardener training begins in September. We will have two informational sessions in August for you to see if the Master Gardeners is a good way for you to serve our community and make some great friends. Check out our website for more information: tulsamastergardeners.or

How to Control Bagworms

Control of Bagworms

Brian Jervis: Ask a Master Gardener

Sunday, July 7, 2019

Q: It seems like every year about this time I get bagworms on my evergreen trees. Why does that occur and what can I do about it? Rob W., Broken Arrow

A: The first evidence of Oklahoma bagworm infestation appears in early June on our arborvitae, juniper, pine, spruce and red cedars. So June and July are the months to scout out and remove those pesky bagworms that appear on our evergreens. Look for small cocoons that are decorated with organic material from the host tree and are attached to such with silk-like threads. While a mild infestation is mostly a cosmetic issue, a heavy infestation can actually defoliate and kill smaller plants. And once a plant becomes infected, the bagworm then becomes a persistent problem unless controlled. Thus, breaking the annual cycle is critical for the health of our evergreens.

The life cycle

Although the small bags start to appear in June, the bagworm’s life cycle actually begins the previous fall when eggs are laid and overwintered within the bags of 1-year-old females. The eggs hatch in April, and the young larvae begin to feed and construct their personal summer palaces.

Bagworm caterpillars then feed for about six weeks, enlarging the bag as they grow and withdrawing into it when disturbed. When the larvae are mature, they fasten the bag to a plant stem or branch with a silk-like thread. Pupation occurs in the bag in late summer, and in the fall, the males emerge and start their search for wingless females who are immobilized in their bags. After mating, the females lay hundreds of white eggs and then evacuate the bag and die. The eggs remain protected within the bag until they hatch the following June. Fortunately, these bag decorators only produce one generation per year.

Bagworms are found in most states east of the Rocky Mountains and are common to all areas of Oklahoma. Although bagworms prefer evergreens, they can be found on bald cypress, maple, box elder, sycamore, willow, black locust and oaks. Fortunately, activity by natural enemies, such as wasps, birds and predatory insects, help curb bagworm populations, which helps to explain population fluctuations from year to year.

Control measures

Small infestations can be reduced by simply handpicking the bags anytime of the year. Once picked, be sure to burn or destroy the bags and their viable eggs.

Chemical controls are a more complete approach and are effective if applied when the larvae are small in early June in Oklahoma. Bt (Bacillus thuringiensis) kurstaki is a bacterial insecticide reported to provide good control of bagworms. Also effective are products that contain the active ingredient spinosad, another microbial agent. Be sure to read and follow all label directions.

Insecticides must be ingested by the caterpillars or larvae to achieve kill, so be patient as it will take some time to see results. Repeat application two weeks following initial application may be needed because not all eggs hatch at the same time or there may be wind-spread migration from other host trees.

Although it may be a little too late to go to the full pesticide route this year, you can still hand-pick and destroy the bags, and now, be armed with the needed information to get ahead of the situation next year.

Garden tips

• Watch for tiny, sap-sucking insects called aphids on roses, perennial flowers, shrubs and vegetables (especially tomatoes). They produce a sticky substance called “honeydew”. Many can be dislodged simply with a hard spray from your garden hose or two applications of insecticidal soap will usually greatly reduce any aphid damage to your plants.

• Crapemyrtles are one of the few shrubs that should be planted in the middle of summer. Growth of new roots of these plants occurs best with summer soil temperatures.

• For all your plants (ornamental or vegetable) mulching and correct watering are the keys to surviving the heat of the summer. Mulch conserves water and reduces ground temperature.

• Fescue lawns need 2 inches of water per week to survive summer. Bermuda grass needs about half that amount. Watering less frequently and more deeply is much better than daily shallow watering as it coaxes the roots to go deeper which promotes survival during hot, dry spells.

• Brown patch disease of fescue lawns is appearing now which is related to excessive rains, heat and high humidity. Wet grass leaves promote the disease. Therefore, watering in the mornings which allows the leaves to dry during the day, leads to less likelihood of infections. Fungicides are available, but OSU feels the fungicides that are available to homeowners are not nearly as effective as those available to professional licensed applicators. Note that all such chemicals will only prevent new disease at best.