Poinsettia Care

Poinsettia Care

Tom Ingram: Ask a Master Gardener

Sunday, December 23, 2018

Q: I love my beautiful Christmas poinsettia. How can I best care for this lovely plant? MP

A: Poinsettias are a native plant in Mexico but were introduced to the United States by the first U.S. ambassador to Mexico: Joel Poinsett (thus the name). In states without harsh winters, such as Florida or California, they can be grown in the landscape. But in Oklahoma, keeping your poinsettia until next year comes with some challenges.

An interesting fact many people do not know about poinsettias is that those colorful leaves are not part of the poinsettia flower. They are specialized leaves called bracts. The flower is the yellow part, which is surrounded by the colorful bracts. Poinsettias with red bracts are typically the most popular, but plants are available with yellow, orange, pink, white and variegated bracts.

Your poinsettia will be the happiest indoors with temperatures between 60 and 70 degrees. Try to avoid cold drafts or excessive heat from your heating system. And keep the plant away from windows, as the cold glass could damage your plant.

Light is important, so place your plant in a place where it will receive at least six to eight hours of light a day.

Moisture for your plant is also critical, and you can assess moisture by feeling the growing medium or using a water moisture meter. Water the top when it starts to feel dry. Slight wilting is not problematic, but do not allow the plant to dry out, as this will accelerate bract drop.

Do not water when the growing medium is already wet as this will encourage root rot and tend to suffocate the plant. Yellow and dropping leaves may lead you to believe the plant is dry and needs water but check the growing medium as symptoms of overwatering can sometime appear to be caused by lack of water.

Oftentimes, people will ask us if they can somehow save their poinsettias to keep them until the following year. The answer is yes, but it is much easier to just discard your poinsettia and purchase another one next year.

If you do decide to give it a shot, in September you will need to begin a fairly stringent regimen of forcing the plants to bloom. This schedule includes leaving the plants in a sunny window during the day but putting them in complete darkness each evening. This daily procedure will likely need to be repeated each day from September through Thanksgiving to give you good bract color. If you would like to try, we have a detailed fact sheet from Oklahoma State University in the Hot Topics section of our website. (tulsamastergardeners.org).

Whether you want to attempt to re-flower your existing poinsettia or just purchase a new one next year, poinsettias are a colorful part of the American Christmas tradition.

Garden tips

• Don’t forget to keep the compost pile watered. The decay process to produce garden-friendly compost continues in winter if the pile is large enough and kept watered and turned.
• Cover strawberry plants with a mulch about 3-4 inches thick if plants are prone to winter injury.
• Wait to prune fruit trees until late February or March.

Christmas Tree Selection and Care

Selecting and Caring for Christmas Trees

Brian Jervis: Ask a Master Gardener

Sunday, December 9, 2018

Q: I am a little late getting a Christmas tree this year, any suggestions on picking a tree and how to care for it? LB

A: I think a lot of us are in the same boat, so here’s some information on selecting trees and caring for them while they are in your home.

This seems like a no-brainer, but give some thought to where your tree will be displayed. Consider height, width and color. Will you only see your tree from one side or will it be visible?  

Next, decide if you want to purchase a pre-cut tree from one of the sources around town or if you want to get yours from an area Christmas tree farm. If you decide on harvesting your own tree, a quick search on the web will provide you with several areas.

Oklahoma has several native-grown trees appropriate for Christmas trees, such as Virginia pine, Leyland cypress, white pine and Arizona cypress. You will find good options in pre-cut varieties, such as Fraser fir, Noble fir and Nordmann fir, all of which have wonderful fragrances and good needle retention. Each of these will also hold ornaments well.

When selecting your tree, pay attention to the freshness of the tree. To determine freshness, you can bend the needles. Fresh needles on firs and spruces will snap kind of like a carrot and are not brittle. Pine needles will bend but break only if they are dry. Of course, the freshest of trees are those you cut yourself and take home.

Once you get your tree home, you should saw about an inch off the bottom and place it in a container of water. If you purchased your tree but won’t be bringing it in to decorate for several days, you should store the tree in a cool shaded area.

Once you bring your tree in, keep its base in water the entire period it is in use. No water additives are needed but keeping the base in water is a must.

Be sure the tree stand is strong enough to support your decorated tree without falling over, as decorations can add more weight to your tree than you might think.

Also, make sure your tree is away from heat sources, as these tend to dry out the trees and increase the risk of fire.

Don’t leave the lights lit on the tree unless a responsible person is at home.

Finally, remove the tree before it becomes overly dry. The longer the tree is indoors, the greater the risk of it drying out.

If you follow these tips, you will be well on the way to having a Christmas tree you will remember for years to come.

Garden tips

• Proper care will extend the life of Poinsettias through the holiday season and beyond. They need to have the brightest light possible and kept away from cold windows and heating vents. They prefer a room temperature of 65-75 degrees. They will die or perform poorly with too much or too little water. Feel the soil and when the top inch or so is dry, water with lukewarm water until water emerges from the bottom of the pot. Discard this water. There is no need for fertilizer.
• 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 also will prevent warming of soil on warm winter days that may promote premature cold-sensitive new growth.

Ice-Melt Products--The Good and the Bad

Ice-Melt Products in Your Landscape

Allen Robinson: Ask a Master Gardener

Sunday, November 25, 2018

Q: It appears we may have a cold AND wet winter, so I am planning by buying something that will melt ice on my sidewalks. Will ice-melt products harm my plants and lawn? Randy W., Broken Arrow

A: Products used to melt ice on walks and driveways may harm plants, but this depends on what and how much is used. Most of the chemicals marketed today to melt ice are just salts that lower the freezing point of water. All are useful if the labeled directions are followed carefully.

Four of the most commonly used chemicals are sodium chloride (table salt), calcium chloride, calcium magnesium acetate and urea. All are types of salts, except urea, which is a chemical normally found in fertilizers.

These products thaw ice but also have some undesirable effects. They may cause corrosion of concrete and metal and water pollution, as well as harm to plants.

Sodium chloride is the cheapest and most widely used for ice melt. But it has a significant potential for corrosion and plant damage in high concentrations. Calcium chloride and urea have similar risk for corrosion but are less harmful to plants. Calcium magnesium acetate does not corrode or pollute water and does not harm plants. However, as you may have already guessed, it also is the most expensive.

Damage to plants occurs in two ways — first, when directly splashed on plants; secondarily, when absorbed into the soil. When slush-containing salt comes in contact with a plant, it may cause direct injury to evergreen leaves and buds, as well as stems of deciduous plants. This injury, especially in deciduous plants, could go unsuspected as the damage may not appear until next spring.

Salts that filter into the soil can kill plant roots by dehydrating them. It can also raise the soil pH to undesirable levels, thus affecting the overall health of the plant and its ability to take up proper nutrients. This is the same as fertilizer “burn” that gardeners are familiar with when too much fertilizer is put (or spilled) in one location. In addition, large amounts of sodium from sodium chloride can damage the soil structure, making it less friendly to plants.

So what do you do? The ideal approach to ice and snow is to remove as much as possible by hand. Not exactly what you wanted to hear, right? Then, if you feel it is needed, apply an ice-melt chemical to help remove the last layer. Avoid the “more is better” mindset and always follow label directions. Mixing sand in a 3-to-1 ratio with ice melt can reduce the need for chemicals and provides added traction to feet and tires.

Harmful effects of these chemicals may be minimized by hosing salt off plants, when it is possible. Much of the salt in soils may be removed if irrigated with generous amounts of water. We are fortunate that ice and snows are not long-term winter problems in our area and that most people are able to cope without ice melt chemicals.

Garden tips

• Continue to plant balled and burlapped trees.

• Wrap young, thin-barked trees with a commercial protective material to prevent winter sun-scald.

• Fertilize cool-season grasses like fescue with one pound of nitrogen per 1,000 square feet. This should be the last fertilization for fescue until next spring. Do not fertilize Bermuda or Zoysia until green-up next April.

• Spring-flowering bulbs like hyacinth, narcissus and tulip, which are sold for “forcing,” can be potted indoors for a colorful winter display.

• Tulips can still be planted outdoors through this month.

• Autumn leaves have good uses other than placing them in the trash. They may be mowed directly into the lawn, which will add nutrients and organic matter; they may be shredded with a lawnmower and added to the compost pile; they may be used as mulch or tilled into the soil of your garden beds.

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

• Till plenty of organic material into the soil in preparation for spring planting.

Dealing with Acorns in Your Landscape

Dealing with Acorns in Your Landscape

Tom Ingram: Ask a Master Gardener

Sunday, November 11, 2018

Q: What is up with all the acorns this year? When the wind blows, it sounds like hail hitting the roof! NM

A: I was raking leaves off the patio recently, and I don’t remember the last time I needed a shovel to pick up all the acorns. So at least in my yard and the yards of my neighbors, I agree, this year we seem to have more acorns than usual.

However, just because some of us are experiencing a bumper crop, this may not be true throughout the region. These “mast” years (as these large acorn crops are called) can be localized, as the main contributor to fruit production is the weather, and as we know, weather can vary depending on your location and particular microclimate. However, one large oak having a particularly good year can drop up to 10,000 acorns in a mast year. And, yes, that can get noisy on the roof!

The primary weather factors affecting acorn development are spring frosts, summer droughts and fall rains. When the oak trees determine the danger of a spring frost has passed, they begin to flower. Oaks are what we call monoecious. This means that a single oak contains male and female flowers.

If you have an oak tree in your yard, you are probably familiar with the male oak flower as they are those long, worm-like growths that contain a number of flowers arranged like beads on a string. These flowers produce the pollen that tends to give our patios and cars a green tint in the spring. In contrast, the female flowers are quite small and often resemble leaf buds.

The spring winds blow pollen from tree to tree pollinating the female flowers. Interestingly, the acorns of white oaks mature within the year while acorns of red oaks mature over a period of two years.

Some of these acorns may grow up to become oak trees, but others will serve as a source of protein for blue jays, wild turkeys, rodents, deer and bears. Secondarily, if we have a year of larger than normal acorn production, depending on the reproduction cycles of the animals, we can expect surges in the populations of mice, squirrels, chipmunks, deer, bears, turkeys, etc. While this may be good news for some, unfortunately, a rise in mouse and deer populations can secondarily contribute to an increase in the tick population as well.

Even though the noise from the shower of acorns can be unsettling and the quantity we need to clean up in our yards a nuisance, these acorns remain an important part of our natural ecosystem.

Garden tips

• Leftover garden seeds can be stored in an airtight container in the refrigerator or freezer until next planting season. Discard seeds more than 3 years old.
• The garden centers still have large selections of spring-blooming bulbs for sale. If you intend to plant bulbs, buy them and plant soon. Tulips can still be successfully planted through the middle of November.
• Be sure to keep leaves off newly seeded fescue. The sprouts will die without sun and air exposure.

Fall Gardening Tips For the Homeowner

Fall Gardening Suggestions

Brian Jervis: Ask a Master Gardener

Sunday, October 28, 2018

Q: I am trying to get my yard, flowerbeds and garden ready for winter. What are some of the things that should be at the top of my list to do (and not do)? — Rick A., Tulsa

A: Good question. Many people ask us about this about now. There are many things that we as gardeners can be doing right now to get ahead of old man winter, who will soon be knocking at our doorstep. Here are a few:

• Seed/re-seed fescue: This is a tough call. Theoretically, the time has passed to do this (up to mid-October) but, if we were to have a mild late fall/early winter, seeds may still germinate. However, if it should turn cold quickly, they will not germinate. Check your weather crystal ball to decide.

• Keep leaves off of newly seeded fescue to prevent damage to the sprouts. A great way to do this is to shred them into small pieces using a recycle-type lawn mower.

• Mow and neatly edge warm-season grasses (i.e. Bermuda, Zoysia, etc.) before the first killing frost.

• 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 and summer stress if planted in the previous fall.

• Plant cool-season annuals like pansies, ornamental cabbage, snapdragons and dusty miller. It is also not too late to plant tulip bulbs for spring color.

• Plant cool-season veggies: broccoli, cauliflower, lettuce, kale, chard, cabbage, collards, spinach, radishes, onions, garlic, turnips, beets and carrots.

• Prune herbs like rosemary, thyme, and sage; prune vegetables such as asparagus and rhubarb, as well as blackberries.

• Divide/plant peonies, daylilies, ornamental grasses, hostas and other spring-flowering perennials. Dig and store tender perennials (i.e. dahlias, caladiums, etc.) in a cool, dry location. Heavily mulch cannas and elephant ears.

• Mulch all beds or plant a cover crop (e.g. rye or vetch) to help moderate soil temperature, increase levels of organic materials to add nutrients, protect the soil from erosion and suppress weed growth. And planting legumes in your garden (e.g. clover, field peas) can increase the levels of available nitrogen for garden vegetables next spring.

• Pull up all dead plants and remove evasive weeds.

• Cover water gardens with either netting or a pond cover to keep out falling leaves.

• Remove garden debris to prevent many garden pests and diseases from overwintering in these materials.

• Prepare your garden soil for spring by tilling. This will break up weeds and expose otherwise hidden grubs.

• Clean up and store garden tools.

And there are a few things that we should NOT do right now, such as:

• Do not trim rose bushes. Given a few warm days that might occur afterward, those new cuts may spawn new growth, which will be readily killed by the first freeze. This can cause an attractive location for disease to enter the plant. Exception: Prune out dead or diseased limbs on trees and shrubs.

• Do not plant bare-root trees at this time. Wait for spring.

• Do not fertilize warm-season grasses or garden beds. Wait for spring.

Twig Girdler Insects

Limbs on Ground Under Tree May Be Due to Twig Girdler Insect

Tom Ingram: Ask a Master Gardener

Sunday, October 14, 2018

Q: I have been finding the tips of branches underneath my trees that look like they have been chewed off. What is causing this? DK

A: The culprit is likely an insect called a twig girdler. Adults are long-horned beetles ranging from 1/2 to 5/8 inches in length. They are grayish brown with antennae typically at least as long as the body. The larvae are whitish, cylindrical, legless grubs that grow to about 3/4 inch in length.

Twig girdlers typically prefer pecan, hickory, persimmon and elm. But, they will also enjoy oaks, honey locust, hackberry, poplar, dogwood, and various fruit trees.

This time of year it is not unusual to see these chewed off branches on the ground around trees the twig girdlers call home. Preferred branches tend to be 1/4 to 1/2 an inch in diameter.

Adult twig girdlers emerge from late August to early October and begin to feed on the tender bark found near the branch ends. While feeding they find a mate and the female deposits her eggs underneath the bark.

There are typically three to eight eggs deposited in each twig, but they may contain up to 40 eggs.

The females live around six to 10 weeks and repeat this process several times laying up to 200 eggs that begin to hatch in about three weeks.

Eggs cannot survive in a living twig, so the girdler chews almost all the way through the branch causing the branch to die. It then typically falls to the ground due to its weight or from the wind.

After hatching, the larvae overwinter in the dead twig, feeding on the woody portion of the branch.

After a 12- to 14-day pupation period during August and September the following year, the adult chews a hole in the bark to escape and the process begins again.

It is not uncommon to see the ground almost covered with twigs in heavily infested trees. Young trees can take on a deformed appearance over the years due to a twig girdler infestation. This girdling not only affects the beauty of the tree but can also reduce yields in fruiting trees.

If you are finding these chewed off branches under your trees, your best strategy is to pick up those twigs and throw them away. This removes the insect from your yard and prevents the larvae from maturing and doing damage again next year.

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 re-pot 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.

Fall is the Best Time to Plant Trees

Planting Trees in Fall

Allen Robinson: Ask a Master Gardener

Sunday, September 30, 2018

Q: Is it true that fall is a good time to plant new trees? If so, what do I need to do to be successful? Alex R., Tulsa

A: Fall is clearly the best time to plant most container-grown deciduous trees and those with balled and burlapped (B&B) root balls. This is because, in the fall, the trees have huge energy stores that are used for growing new roots rather than producing leaves and fruit. This will allow the tree to enter the following growing season much better able to handle the summer stresses. Also, although the air temperatures are dropping, the ground temperatures are still warm enough to encourage good root development for some time. The exception to this rule is that evergreen trees and bare-rooted plants should be planted in early spring.

Of all of the newly planted trees that die in the first few years, the problem is almost always due to faulty planting techniques and inadequate aftercare. So let’s discuss this.

First, it is best to dig a wide but shallow, saucer-shaped hole two to three times the diameter of the tree’s root ball and no deeper than the root ball itself. If you simply dig a hole the size of the root ball, particularly in clay soil, it will be similar to planting it in a clay pot and the tree will be either too dry or too wet much of the time. If you are planting in shallow clay soils, the hole should be shallow enough to elevate the crown of the root ball 2-3 inches above grade to help with overall root system drainage.

When planting trees, it is recommended that you use only native soil for backfill. Studies have shown that trees do better if no amendments are added back to the native soil, as it may delay establishment and promote disease. If you decide to fertilize, apply a slow-release type only to the top of the soil after planting.

Eliminating grass from the tree’s base significantly improves growth rate and health. After planting, apply 2-4 inches of loose mulch in a 4- to 6-foot circle around the base of the tree and keep it well-mulched for the first three years. This circle will keep unwanted grass away from the dripline and commercial weed eaters away from the tree trunk.

All newly planted trees need supplemental watering for the first three years until a mature root system develops. They need at least 1 inch of water per week and more if extremely hot and windy conditions exist. Wilting of the trees’ leaves may indicate a need for more water, but be aware that too much water can also produce wilting. If in doubt, simply feel the sub-soil.

If the tree is on a slope or in a windy area, stake it only until the tree feels firm in the ground, which could take up to one year. After the first growing season, remove all stakes. If not removed, the stakes will adversely affect the tree’s structural integrity and delay tree growth.

For more detailed information on this subject, see OSU Fact Sheet L-440 (Tree Planting Guide).

Garden tips

• You can continue to replant or establish cool-season lawns like fescue until mid-month. The mowing height for fescue should be lowered to approximately 2½ inches for fall and winter cutting.

• Plant cool-season annuals like pansies, ornamental cabbage or kale, snapdragons and dusty miller when temperatures begin to cool. Begin planting spring-flowering bulbs like tulips, hyacinths, crocus and daffodils.

• There is still time to plant radishes and mustard in the fall garden. 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 water temperatures near 50 degrees. Stop feeding fish at this temperature. Close the water garden for the winter by placing hardy plants in the deeper areas of the pool and cover it with bird netting to catch dropping leaves during the winter months.

Reseeding Fescue Lawns in Fall

Reseeding Tall Fescue in Fall

Brian Jervis: Ask a Master Gardener

Sunday, September 16, 2018

Q: It seems like my fescue thinned out this summer. How do I re-seed and when is the best time? DH

A: Fescue is a good choice for areas of your landscape that get some shade. It thrives in spring and winter but struggles with our Oklahoma summers. As a result, most of us need to re-seed our fescue each year to keep a thick, healthy turf.

Cool-season grasses, like fescue, germinate best when the soil temperature is in the 70-degree range. This happens in the spring and fall, but fall is the best time to re-seed as this gives your new fescue the fall, winter and spring to develop a healthy root system. The last half of September through the first half of October usually gives us the soil temperature we need.

Oklahoma is fortunate to have the Oklahoma Mesonet (mesonet.org), which provides us with a wealth of information, including the soil temperature for each county. At this writing, 2-inch soil temperature in Tulsa County is 72 degrees, so this is perfect.

For optimal results, we recommend purchasing seed with a blend of at least three different types of seed rather than a single cultivar. Doing so not only increases your likelihood of success, but also combining grasses tends to reduce the incidence of disease as each type tends to mask the weaknesses of the others.

It is also a good idea to prepare your soil rather than just sprinkle seed on the ground. The upper layer of soil tends to develop a crust so seeds dropped on this hard surface will either blow or wash away before having a chance to germinate. Breaking up the soil can be done with a rake or by perhaps renting a tiller or verticutter for difficult situations.

Seed should be sown evenly with either a rotary or drop spreader and applied at a rate of 3 to 6 pounds per 1,000 square feet when reseeding.

Seeds must have water to germinate, which typically means watering twice a day for a few minutes during the first two to three weeks. The key is to keep the seeds moist. Once the seedlings are 1 to 2 inches tall, you can begin watering less frequently and for longer periods.

Fertilization will also be necessary, and we recommend getting a soil test from the OSU Extension so that you will know exactly which nutrients your soil requires for best results.

One word of caution: If you plan to re-seed this fall, do not use a weed pre-emergent as this will not only work to prevent weeds from growing but will also prevent your new fescue from growing.

We have quite a bit of information at our Diagnostic Center and on our website to help you maintain your new and existing turf: click “Lawn & Garden Help” and then select “Turfgrass” for fact sheets and videos (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, which do well in our area.

Control of Bagworms on Trees and Shrubs

Control of Bagworms on Trees and Shrubs

Allen Robinson: Ask a Master Gardener

Sunday, September 2, 2018

Q: I am seeing lots of bagworms on my cedar trees and other trees right now. What can I do to get rid of them? Charlotte S., Tulsa

A: Bagworms are common pests on eastern red cedar, other junipers, arbor vitae and sometimes on bald cypress, elms, pines, willows, maples and others. They are unique in that once they form their protective bag later in the summer, insecticides are not helpful. Treatment should begin soon after the eggs hatch in late spring.

The cycle of worm production begins in the spring when eggs that have overwintered in bags hatch. Newly hatched larvae develop small, upright bags while feeding on the plant. Initially, the bags are less than ¼ inch but, when mature, they can reach up to 2 inches in length. Once mature, the larvae close off the bag and fix it to the tree. In mid-summer, the males emerge from bags, fly around and mate with females who never leave the bags. The females lay eggs in the bag and then die. The cycle begins anew in the following spring.

For smaller trees with small infestations, the easiest treatment is to simply pull the bags off and destroy them. This can be done at any time of the year. Be sure to burn them or place them in a well-sealed bag to destroy the bags and their viable eggs. Trees that have heavy infestations yearly should be treated with an insecticide because large numbers can completely defoliate and kill smaller trees.

Insecticide treatment must be done soon after the larvae hatch in late May or early June. No treatment is considered effective once the bag is closed. Be patient as most insecticides will require repeat applications every seven to 10 days for two to three treatments because not all eggs hatch at the same time or there may be migration (wind dispersal of small larvae during June) from other host trees.

There are two relatively safe organic insecticides. The safest is Bacillus thuringiensis kurstaki, or “Bt,” sold as Thuricide and other brands. The good news about this herbicide is that it is not harmful to people, pets or fish. It is a bacterium that infects the bagworm and causes it to starve. It must be sprayed directly on young larvae.

Another biological insecticide derived from a bacterium is Spinosad, a microbial agent that is sold in several brands including Fertilome Borer, Bagworm, Tent Caterpillar and Leaf Miner Spray. Spinosad has contact and systemic activity on target insects. It, too, has low toxicity and a good environmental profile. Be sure to always read all label directions.

Other nonorganic manufactured insecticides are labeled for bagworms and are effective in controlling young worms. However, these insecticides also kill the parasites and predators that normally keep bagworms under control.

So, while the most viable way to rid your trees of bagworms at this time of year is to pick them by hand and destroy them, consider keeping this information handy so that next year the problem can be dealt with in late spring.

Garden tips

• If your tomatoes are too tall and gangly, 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.
• Reseeding fescue is best done from mid-September through mid-October. If you plan on reseeding, begin scouting for good seed now. Purchase a fescue blend of three or more varieties, with or without Kentucky bluegrass. Read the label on the seed bag. A good blend will have 0.01 percent or less of undesirable “other” crop seeds.
• In the fall, strawberry plants build up food reserves and form fruit buds for the next year’s crop. They should be fertilized between mid-August and mid-September with a nitrogen fertilizer, such as ammonium sulfate, at a rate of 1½ pounds per 100-foot row. Apply 1 inch of water if no rain is expected.
• You have all of September to plant cool-season vegetables like spinach, leaf lettuce, mustard and radishes, and until the middle of September to plant rutabagas, Swiss chard, garlic and turnips.
• The last nitrogen fertilizer application of the year on warm-season grasses should be applied no later than Sept. 15.

Don't Miss Out on Fall Vegetable Gardening

Fall Vegetable Gardening is Not to Be Missed

Tom Ingram: Ask a Master Gardener

Sunday, August 19, 2018

Q: I plant a vegetable garden every year in the spring, but I have never tried a fall vegetable garden. What can I plant in a fall garden and when do I plant? SM

A: Oftentimes, fall vegetable gardens get overlooked because we don’t know what to plant, or maybe we are just tired from our spring and summer gardens and ready to call it quits. Either way, growing fresh vegetables can be a year-round activity. And what you may 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.

You can divide fall crops into two groups: “tender” and “semi-hardy.” “Tender” means these vegetables will need to reach full maturity and production before the first frost brings their season to an end. “Semi-hardy” means they may continue to grow and be harvested 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.

With the cooler weather we are having (watch it change since I wrote that), now is the perfect time to plant a variety of tender and semi-hardy crops. Tender varieties you could plant now would include bush beans, lima beans, cucumber and squash. Semi-hardy crops would include cabbage and cauliflower (transplants), collards, potatoes (seed potatoes), kale, kohlrabi, lettuce (a little late, but I did anyway), parsnips, radishes, swiss chard and turnips.

Starting 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).

Mulch should be an important part of your garden strategy any time of year as mulch helps retain moisture, as well as reduces weeding. In addition, mulch controls soil temperature swings during the day, which helps keep those tender roots happy.

Oftentimes, people contact us wanting to know what type of fertilizer would be best for their situation and how much they should use. There is really no good way to answer this question without testing your soil.

Getting a soil test is not hard. All you need to do is get 15-20 samples of soil from your garden and put them in a bucket. Be sure to dig down about 6 inches with your trowel for these samples. Remove any nonsoil debris and mix up the soil. Then, bring about a sandwich bag’s worth to the extension office. We’ll send it off to Oklahoma State University, and within about 2 weeks, you will know the basic nutrient content of your soil and how to best amend it for optimal results. The test will cost you $10, but in my view, it is likely the best $10 you will ever spend. Happy gardening!

Garden tips

• 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.
• This time of the year is generally not the best time to prune, but if you have damage to trees and shrubs due to storms, prune out the damage now.

What is a Master Gardener and How do I Become One?

Becoming a Master Gardener

Tom Ingram: Ask a Master Gardener

Sunday, August 05, 2018

Q: At the beginning of each of the classes we teach in elementary schools throughout Tulsa County, we typically ask the students a question: Who knows what a Master Gardener is?

A: We get all kinds of answers (as you might imagine) — “someone who is good at gardening” (we hope), “someone who likes insects” (most of the time) and “someone who likes plants” (always yes.)

Truth is, the question does not come with a simple answer because Master Gardeners do so many different things.

By definition, Master Gardeners are volunteer educators for the Oklahoma State University Extension service on a mission to provide research-based horticultural information to local home gardeners and the community. But, that mission can take many forms.

One of the ways we fulfill that mission is by staffing a horticultural Diagnostic Center at the OSU Extension office Monday through Friday. Between the hours of 9 a.m. and 4 p.m., you can find Master Gardeners on hand to answer your questions via phone, email or in person. Outside our Diagnostic Center, you will find our beautiful Master Gardener-maintained demonstration garden containing more than 200 annuals, perennials, shrubs and trees.

We also teach a variety of classes, such as our spring and fall Lunch and Learn series at the Tulsa Central Library, or our yearly Urban Gardener classes. Topics include plant biology, soil chemistry, growing fruits and vegetables, lawn care, tress and shrubs, flowers, container gardening, etc.

We mentioned the public schools. Master Gardeners teach a variety of science-based classes to elementary school students throughout Tulsa County. Last year, we taught these classes to approximately 16,500 students.

In addition, each year we also host an Insect Adventure for more than 1,000 third-graders, which helps these students gain a respect for the wonderful variety of insects we share this planet with and the many benefits they provide.

You may also have seen Master Gardeners at an Herb Festival or perhaps at our beautiful exhibit at the Home & Garden Show. Or, you may have visited one of our homes in the Master Gardener Garden Tour we host each spring.

Some Master Gardeners visit nursing homes to spend time with seniors while engaging in a little horticultural therapy to brighten their day. Others landscape yards for Habitat for Humanity homes so these new homeowners don’t just get a house but a beautifully landscaped home. And other Master Gardeners spend hours planting and maintaining beautiful flowers in planters in the Brookside and Blue Dome districts to help keep Tulsa beautiful.

So, now that you know what a Master Gardener does, do you want to come join us? At 10 a.m. Aug. 8 and 1 p.m. Aug. 15, you can attend a presentation at the OSU Extension (4116 E. 15th St.), where you can find out the requirements to become a Master Gardener and fill out an application. This enrollment only happens once a year, so if you have an interest, be sure to attend one of these presentations.

Garden tips

• 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 September.
• Mowing heights for cool-season turf grasses should be at 3 inches during hot, dry summer months. Gradually raise mowing height of Bermuda 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, after it cools, they will be fertile again and the taste of the cucumbers will improve.

Azalea Problems and Proper Care

Azalea Care

Brian Jervis: Ask a Master Gardener

Sunday, July 22, 2018

Q: I have azalea bushes that are so beautiful in the spring but then develop problems over the summer. Should I just live with these issues or is there something I can do to help make them look better through the summer? Michelle T., Broken Arrow

A: Landscapes bursting with healthy plants give us splashes of color that change with the seasons, and azaleas are ideal centerpieces for flowering shrub beds, containers and even hedges.

However, the dream of such garden beauty sometimes comes into question when spots and holes appear in leaves, the foliage turns yellow or flower buds remain closed. While azaleas can withstand many of the insect and disease problems that plague other plants, there are still a few problems that can occur.

First of all, plant in the right location (east facing with good morning sun is the best), with good drainage and air circulation between plants to help prevent problems. However, when that is not sufficient, here are a few of the most common offenders:

Aphids: These may appear on the stems of any plant when the weather is humid and plants are too close together without enough air circulation. Treat aphids with a hard spray of water from the hose.

Lace bugs/spider mites: Azalea lace bugs make up about 90 percent of all azalea pest problems. They feed on leaves, creating speckled areas on the leaf surface. Spider mites cause white stippling on leaves first, but then the area turns a rust or gray color. Both can be treated with insecticidal soap, horticultural oils or a systemic insecticide that includes the ingredient imidacloprid. Use it as a soil drench once yearly after blooming to avoid harming bees.

Fungus-related issues: Leaf galls, rust, petal blight and leaf spot are caused by fungus. Petal blight appears as tiny white spots on flowers. Leaf spot manifests as brown blotches that grow in size. Treat with a fungicide.

Root rot/water mold: Azaleas may also be impacted by another fungus that causes root rot, sometimes called water mold. Azaleas that stand in water during warm weather are particularly susceptible. This occurs mostly when azaleas are planted as a foundation plant near a down spout. This fungus spreads fast, so watch for yellowing leaves and wilting plants.

Iron Chlorosis: Azaleas prefer acidic soils. If not planted in such, leaves will turn yellow. With this condition, a soil test is always in order, which can confirm the actual soil pH.

To assist in preventing these issues, azaleas should be mulched with several inches of pine bark, and some of the bark should be incorporated directly into the planting soil to help add oxygen and ensure thorough drainage.

Protect your valuable and beloved plants with regular attention, looking carefully for potential problems along stems and branches, as well as under leaves. And, when it comes to chemicals, more is never better. Small infections and infestations may go unnoticed, only to grow into larger issues later. Therefore, it is best to examine your azaleas every time you water.

For more information and assistance with azaleas, drop by the Tulsa County Extension Office or call the Master Gardener hotline at 918-746-3701 to speak with a Tulsa Master Gardener.

Garden tips

·        When watering your lawn, ornamentals or vegetables, always do so in the morning, if possible. If watered in the evening, plants will go into the night still moist. Most disease-causing organisms need moisture and, because they grow best at night, leaving leaves wet in the evening will promote many plant diseases.

·        Bulb onions are ready to harvest when the tops fall over. They should be removed and allowed to dry in a well-ventilated, shaded area. After the tops are completely dry, they may be stored in a cool, dry area.

·        Tomato production stops in the heat of the summer. Most tomato pollen becomes infertile and blossoms drop off when the night temperatures are above 70 degrees and daytime temperatures are above 92 degrees for a few days. Tall, spindly tomato plants with scarce fruit are usually due to either too much nitrogen fertilizer or too much shade. If this occurs, cut them back by ⅓. New growth and fertile blossoms will develop when it cools in the fall.