Moving Plants Outdoors for Summer

Moving Plants Outdoors for Summer

Brian Jervis: Master Gardener

Tuesday, May 16

Q: Is it a good idea to move my houseplants outside for the summer? Should they be repotted? K.S., Tulsa

A: Yes, it is a good idea to move most houseplants outside for summer, but you must respect their individual requirements for temperature and sunlight.

Most houseplants are tolerant of reduced lighting indoors, but they usually originated as outdoor plants. Your plant would like to be outdoors again if the conditions are favorable.

Do not move houseplants outdoors until all danger of frost has cleared and the outdoor temperature is about the same as indoors. When moving plants, they should be placed in shade for a couple of weeks, then gradually moved to full sun or sun/shade, depending on their requirements.

Some plants, such as one of the Chinese evergreen cultivars, cannot tolerate sunshine. They get sunburned and should be located in dappled or full shade. Other plants such as the cacti, bougainvillea, hibiscus, plumeria and others do best in full sun.

Because houseplants usually grow much more rapidly outdoors in summer, they need more water and fertilizer. Depending on the plant, a balanced liquid fertilizer every 2-3 weeks or so should be a good plan. Water requirements during the hot summer may mean watering every day or even twice daily, depending on the plant, the weather and the type of potting soil.

Inspect the plant’s roots when moving outside. If the plant has filled the pot with roots (called being “root-bound”), it grows more slowly and may eventually die. Hints that the plant has this problem are if the plant needs frequent watering or if large numbers of roots come out of the container’s drainage holes. Remove the plant from the pot, and if you see mostly dense roots growing in circles, it probably should be repotted. An exception to this is if the plant looks healthy, and you do not wish for it to grow any faster or taller, keep the plant as is.

Another indication for repotting is if a white crust has formed on the soil. This is an undesirable accumulation of salt residue from fertilizers.

Select a new pot an inch or two larger than the old one. The soil for the new pot should be a commercial potting soil, which will ensure good drainage. Never use soil from your garden; it drains poorly and may carry disease. Before planting, consider making three to four vertical slits in the root-ball of root-bound plants, which have large numbers of circling roots.

Place a coffee filter or fine screen at the bottom of the pot to keep soil from leaking out. It is not recommended that a pile of potting shards or gravel be used on the bottom. Rather than improving drainage, these materials placed over the pot’s drainage holes may actually prevent drainage by producing a “perched water table” zone just above the gravel. This has to do with the physics of water drainage and can be unhealthy for the lower roots.

Garden tips

• Clean out water garden and divide and repot water garden plants. Begin feeding fish when water temperatures are higher than 50 degrees.
• Plant warm-season vegetable crops such as watermelon, cantaloupe, cucumber, eggplant, okra, sweet potatoes and other warm-season crops now.
• Fruit trees, especially apples and peaches, must have their fruit thinned for best production. Prune apples 4-6 inches apart and peaches 6-8 inches. This will ensure larger fruit and less damage to limbs. If not thinned, the tree's resources will be used to such an extent that next year’s crop will suffer.
• Late May is the best time to control borers in the orchard. Contact OSU Tulsa Master Gardeners for fruit tree spray recommendations.

Controlling Weeds in Your Lawn

Controlling Weeds in Your Lawn

Bill Sevier: Master Gardener

Tuesday, May 9, 2017

Q: What is the best way to get rid of weeds in my lawn? J.A., Tulsa

A: The most effective way to prevent weeds is to have a green, thick, healthy lawn, which will prevent weed seeds from sprouting. Unfortunately, most of us don’t have a uniformly thick lawn and have to deal with weeds growing in the thin or bare spots. There is a wide range of tolerances for weeds in the lawn. The purist wants no weeds while others may adhere to the adage “one man’s weed is another man’s wildflower.”

OSU’s lawn maintenance information sheets — one on Bermuda, the other on fescue — are available on the Master Gardener website, tulsamastergardeners.org, in the lawn and garden section. These sheets describe all aspects of lawn care, including weed control, and may contain all the information you need for your lawn care.

In terms of chemical control, there are two approaches — prevention with pre-emergent herbicides and eliminating existing weeds with the post-emergent variety.

Pre-emergent herbicides are best used in the spring to prevent crabgrass and most summer weeds and again in fall to deal with the winter weeds such as henbit, chickweed and annual bluegrass (Poa annua). Pre-emergent herbicides recommended by OSU are listed on the above referenced information sheets. It should be understood that when using these herbicides, you will never get 100 percent prevention, and they will be of no benefit unless the instructions are followed in detail.

Post-emergent herbicides available are based on the type of weed. There are three main botanical weed types — broad leaf, such as dandelion; grassy weeds such as crabgrass, and sedges like yellow nutsedge (nutgrass).

Most broad-leaved weeds are best treated with one of the many brands of herbicides containing a chemical called “2,4-D.” It usually is mixed in with other herbicides to enhance control. The chemicals in this category are mostly derivatives of plant growth hormones and have the greatest effect on growing weeds in spring and fall. After a weed reaches maturity and blooms or produces seeds, their effectiveness is greatly reduced.

Grassy weeds are difficult. The best herbicide for weeds such as mature crabgrass, Dallisgrass, orchard grass and the like has been taken off the market. Herbicides available now for mature crabgrass contain a less effective but useful chemical called quinclorac.

The most common sedge in the lawn is yellow nutsedge. This is the slender weed that pokes its head up above grass two days after mowing. Although some broadleaf herbicides are labeled for nutsedge, they are not effective. Products containing imazaquin (Image), halosulfuron (Sedgehammer) and bentazon (Basagran) and sulfentrazone (many brands) are effective.

Again, suggestions by OSU about which chemicals to use and when are in the lawn maintenance documents from the Master Gardener website mentioned above. Be aware that the chemical names mentioned are found in many brands. Also, remember to always read and follow instructions on the label of each brand.

Garden tips

·        Nutsedge weeds are emerging now. Post-emergent treatments are best applied for the first time this month. Make certain warm-season grasses have completed green-up. Nutsedge requires specific treatment for control; standard broadleaved post-emergent herbicides are not effective. Contact the OSU Tulsa County Master Gardeners for recommendations.

·        Plant summer bulbs such as cannas, dahlias, elephant ear, caladiums and gladiolus.

·        Apples and other fruit need thinning for best production. If apples are not thinned, the crop will be of poorer quality this year and small next year. Thin to one apple every 4 inches.

·        Remember, working wet soil will cause significant damage to the soil structure. Give it time to drain from recent rains, before tilling. Damage from tilling while wet may last for a long time.

Common Vegetable Garden Problems

Vegetable Garden Problems

Brian Jervis: Ask A Master Gardener

Tuesday, May 2nd

Q: Last year, my cabbage plants had a problem. They were yellowish and didn’t grow well. What could I be doing wrong? S.C., Tulsa

A: There are a number of problems vegetable growers may face during the growing season. Your stunted and yellow plants may result from a host of things, some of which involve the lack of fertility or unfavorable soil acidity (pH). A soil test will sort this out.

Other causes are compacted poorly draining soil and poor quality of seeds or transplants, along with various insects and diseases. In addition, planting too early in the season when soils are still cold may cause a problem as you describe.

Disease and insect damage is often easy to identify. Insects frequently leave evidence of holes or nibbled areas and may cause yellowing of leaves. Some of these pests are small and difficult to see without a hand lens. Diseases of plants are often associated with brown spots, powdery deposits or rusted areas.

If soil compaction is a problem due to clay soil or planting in a high-traffic area, tilling in composted organic material will help, but the best option for this problem is to plant into a raised bed with good soil.

Other common problems in the vegetable garden involve roots. Inspect them, and if small and poorly developed, the problem may be due to overly wet soil or root damage due to fungal disease or nematodes.

If you experience “blossom drop,” where blossoms form but do not produce fruit and drop from the plant, the cause is usually environmental. The temperatures are either too hot or the nighttime temperatures too cold or the soil is too wet or too dry. Excessive nitrogen fertilizer can also produce blossom drop. The plant can overcome this as conditions improve.

When sun-loving plants are planted in shade or part shade, they often become tall, spindly and unproductive. They grow tall looking for sunlight. Over-fertilization may also cause this problem.

There are some steps you can take to cope with these problems. First is to do a soil test every two to three years and apply only the types of nutrients needed and never develop the mind-set that “more is better.” Another step is to plant your vegetables with attention as to their need for sunlight.

Next is to inspect your garden as often as possible to identify problems, such as insects and disease, which may be dealt with early. Always remove weeds and use mulch to prevent new weed growth, conserve water, moderate temperature and help prevent disease spread.

Something else one can do to improve success is to not walk in or till the garden when soils are wet such as they are now. Tilling wet soil destroys the structure for years to come.

Garden tips

Prune and feed all spring-blooming shrubs, such as azaleas and forsythia, immediately after blooming, if needed. Azaleas need less fertilizer than many shrubs and often a yearly addition of mulch, as it decays, it will add all the nutrients they need.

Cool-season lawns — tall fescue and bluegrass — can be fertilized again. If you did not fertilize in March and April, do so now. Do not fertilize these grasses in summer.

Seeding and sodding of warm-season grasses such as bermudagrass, Buffalograss and zoysiagrass, is best performed in mid-May through the end of June. The soil temperatures are warm enough for germination and growth. These grasses need a long summer growing season to promote winter hardiness.

Galls on Trees and Other Plants are Common and Need No Treatment

Galls on Trees are Common and Need No Treatment

Bill Sevier: April 26

Q: What are these blister-like things on the leaves of my oak tree? Will it harm them? P.T., Tulsa

A: The structure on your leaves is a common oak leaf gall and will not harm a mature tree.

Galls are abnormal growths on plants and come in many different shapes and colors. Several types of pests cause galls, including insects, mites, bacteria, fungi and viruses. These pests specialize and almost always cause galls on a specific plant type — oak galls on oaks and ash galls on ash trees and so forth.

Galls may affect any part of a plant but most commonly are found on stems and leaves. Any time you see a bizarre, abnormal growth on a plant — round, flat, fuzzy or irregular and of one of many different colors not belonging to the plant — it is safe to assume you have found a gall. There are many hundreds of gall types and have been the subject of much folk lore in the past.

Many types of oak galls, such as oak leaf gall, are produced by a tiny wasp about the size of a mosquito. In spring, the wasp lays eggs as the plant is putting on new growth. The egg-laying process produces a growth hormone, which stimulates the plant’s system to grow a protective shell. This shell is the gall, and once formed, it completely seals off the larvae, protecting them from predators and insecticides.

The galls almost never affect a tree’s growth and survival; most homeowners’ main concern is the appearance of the tree when it is heavily infested.

Some types of galls can be detrimental to fruit trees, and insecticidal sprays may be recommended as the wasp is laying eggs in early spring. However, spraying is not suggested for shade trees in the landscape. If the tree is small enough where one can reach the galls, they may be cut out. The infested leaves should be raked and placed in the trash, but otherwise, galls are best ignored.

One unique problem significant to homeowners, which is associated with oak leaf galls, is the “oak leaf itch mite.” There was an outbreak of this mite in the Midwest two years ago, and Tulsa had its share of the mites. The mite has a bite like a chigger, but the bite area tends to be a bit larger and may contain a pustule. As the name indicates, itching is a prominent feature of the bite.

Oak leaf itch mites are produced by a female mite laying eggs in a “marginal oak leaf gall,” where its larvae feed on the galls larvae and reproduce. They are then released by the many thousands. Because of their size, they are spread widely by wind and are able to pass through screens of windows and doors. At present, these mites have no solution other than letting nature control them, which seems to have happened. They may return in the future, but there is no predicting this.

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Garden tips

·        Lace bugs, aphids, spider mites, bagworms, etc. can start popping up in the landscape and garden later this month. Keep a close eye on all plants and use mechanical, cultural and biological control options first.

·        Remove any winter-damaged branches or plants that have not begun to grow. Prune spring-flowering plants as soon as they are finished blooming.

·        Proper watering of newly planted trees and shrubs often means the difference between success and replacement.

·        Do not spade or till wet soil; it will destroy the soils structure and eliminate air spaces which takes a very long time to recover.

Planting Disease Resistant Elm Trees

Master Gardener: Elm hybrids are good choice for shade trees

 Brian Jervis: Master Gardener

 Tuesday, April 18, 2017

Q: I am looking to plant a large shade tree and wonder what my choices are. Is it too risky to plant elm or ash trees due to their diseases? J.C., Tulsa

A: Several species of our great shade trees in the U.S. have suffered from the impact of imported pests and disease, and the process is still ongoing.

Most of our stately chestnuts that were so common in the past were killed due to chestnuts bark fungus, imported from Asia in 1904. In the following 40 years, more than 30 million acres of chestnuts were destroyed in the eastern U.S. However, some hybrids are now available that have excellent resistance to the fungus.

Ash trees are being decimated by the Emerald Ash Borer, an insect introduced into the country in 2002. Until recently, it was found only in states surrounding Oklahoma, but now has been reported infecting ash trees in the northeast part of Oklahoma. It is now found in most every state from Colorado eastward. To date, it has killed many millions of ash trees, no control is developed and will likely kill most of the 8 billion-plus ash trees in the U.S.

The majestic American elm tree, which had covered many of the streets in the U.S. with beautiful canopies, have mostly been destroyed by Dutch elm disease (DED), a fungus introduced in the U.S. around 1930. Elms were used so much in the past that most towns and cities still have an “Elm Street.” Of the 77 million elms in North America, is was estimated that 75 percent had been lost to the disease by 1989. The fungus is spread by the Elm Bark Beetle, and all of the native U.S. elm species are susceptible to the infection.

Since the disease began, horticulturists have been involved with selective breeding of elm survivors of the disease. Now there are several hybrids that have shown good to excellent DED resistance and are a great source of high-canopy shade trees. All are hardy into the USDA zone 4, which may have temperatures as low as -30 degrees.

The best of these hybrids are listed below.

Princeton: Selected years ago for its resistance, fast growth rate and a canopy similar to the original American elm.

Valley Forge: A USDA-recommended cultivar that has excellent disease resistance and form. It also is a rapid grower.

New Harmony: Another USDA selection of an American elm hybrid that appears to have superior form when compared to Princeton and Valley Forge.

St. Croix: Selected from a massive elm in Minnesota. It has good disease resistance.

Prairie Expedition (“Lewis and Clark”): A recent selection from North Dakota State University. Classic vase-shaped American elm form and growth rate, outstanding autumn gold color.

These trees may be difficult to find, but some, such as Princeton, may be found at local nurseries. Most others are available online. You will find no better tree to plant for shade and an aesthetic addition to your landscape.

Garden tips

·       Don’t spray insecticides during fruit tree bloom or pollinators may be killed. Disease sprays can continue according to schedule and labeled directions.

·       Mowing of warm-season lawns is beginning now. Cutting height for bermudagrass and zoysia grass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.

·       Harden off transplants outside in partial protection from sun and wind prior to planting.

·       Hummingbirds arrive in Oklahoma in early April. Get your bird feeders ready using 1 part sugar to 4 parts water. Do not use red food coloring.

For Best Production Fruit and Nuts Need Thinning

Fruit, nut trees benefit from thinning

Bill Sevier Ask a Master Gardener

Tuesday, April 11, 2017

Q: The production of apples on my tree goes in cycles — lots of apples one year and fewer the next. Is there anything I can do to prevent this? S.G., Sand Springs

A: Yes, there is. Every year, you should thin out the apples when they are the size of a quarter so that there are 6-8 inches between each young fruit.

Thinning fruit is important for optimal production in most all fruit and nut trees. There is a reason for this, and it relates to basic plant biology.

Any fruit or nut produced by a tree is dependent on an adequate supply of water, nutrients and energy (mostly sugars). Water and nutrients, such as nitrogen, phosphorus, potassium and others are absorbed from the soil by the roots. To do this, there must be ample amounts of nutrients and water in the soil. Energy comes from photosynthesis. This is the production of sugars, an effect of sunshine on the trees leaves. So for fruit production, a tree needs healthy roots, plenty of leaves and sunshine.

There is a limitation of the amounts of nutrients and energy a plant can supply for growing fruits and nuts. When the demand is greater than the tree can deliver, fruits and nuts are not only small but also do not have the sweetness and flavor expected from that particular variety of tree.

Thinning not only improves quality of fruit, but there is also less chance of unwanted fruit drop, cold injury and limb breakage. Be aware that all fruit trees do not need to be thinned; some varieties will thin themselves of excess fruit early on in development.

The cycling of fruit and nut production (large crop one year and small or no crop the next) is usually due to depletion of energy stores in the tree during a heavy crop year, followed by a need to replace energy supplies and produce little fruit the following year.

Thinning fruit can be painful. For some fruits, such as peaches, upwards of ¾ of the total fruit crop may need to be removed to produce a quality product. Commercial growers of fruits and nuts (mainly pecans) have several ways of thinning their trees. This involves a variety of chemical sprays, as well as some mechanical shaking of trees.

Most homeowners thin what they can reach by hand. When thinning, one should look not only for proper spacing between fruit, but also select the largest and healthiest fruit in a cluster to keep on the tree.

Some of the recommended spacing between fruit when thinning are: Apples 6-8 inches, apricots and plums 4-6 inches, peaches 6 inches. Cherries are not likely to need thinning. Most pear trees also need no thinning unless that variety is prone to cyclic production.

As stated, thinning can be painful but is essential for full-sized tasty fruit and nuts.

Garden tips

·       Termites and ants are swarming now and will be into May. It is essential to identify whether the flying insect is a termite or ant. To tell them apart, one may need a hand lens, but the essentials are this: Termites have no waist — the waist is the same size as the chest — while ants have a tiny waist. Termites have straight antenna; ants antenna are bent. Each have two pairs of wings, the termites are of equal size, while ants have a shortened pair.

·       Termites flying inside your home is significant and an exterminator should be consulted. Termites outdoors could be important, but most are feeding on woody material (old stumps for example) and are doing natures work in breaking down dead organic material. Nevertheless, if you see termites outdoors nearby, your home needs inspection for signs of invasion.

·       March is the second best time of the year to seed cool-season turfgrass; however, fall is the best time to plant.

·       Let spring-flowering bulb foliage remain as long as possible before removing it.

Selecting Vegetables to Grow

Picking the right veggies to grow in Oklahoma

Brian Jervis Ask a Master Gardener

Tuesday, April 4, 2017

Q: What are the best varieties of vegetables to grow in Oklahoma? T.M., Tulsa

A: Our weather extremes present a challenge for many varieties of vegetables. Fortunately, there are some good resources from OSU and elsewhere. OSU fact sheet F-6032, “Vegetable Varieties for the Home Garden in Oklahoma” is a good place to start.

In addition, OSU conducted a vegetable trial in 2014 obtaining information on a wide assortment of vegetables. This is available online by searching for Oklahoma States’ “2014 Vegetable Trial Report.” In particular, this report has a review of the best tomatoes for heat tolerance and taste, which would be of interest to Oklahoma tomato growers.

Another resource worth looking into is the All America Selections website, all-americaselections.org. This organization evaluates a host of new cultivars of ornamentals and vegetables and submits a yearly list of its winners. A partial selection of vegetable cultivar winners and the judges’ comments are below.

Candle Fire okra: This okra has bright red pods that are round, not ribbed, on red stems. The Candle Fire okra was graded not only for productivity, taste, texture and tenderness, but also for ornamental value. It was noted to be tolerant of heat and disease resistant, which is particularly pertinent to gardeners in our area. It was recommended for its fruit and ornamental value.

Mad Hatter Pepper: This pepper has several assets, not the least of which is its unique shape. The plant is described as a vigorous early producer with high yields. It is a large pepper, with a good taste, according to AAS judges. They describe the taste as “a citrus floral flavor, which remains sweet, only occasionally revealing mild heat near seeds.” Its origin is South America, but this cultivar has been bred for North America. This pepper is worth consideration for appearance and for a healthy food.

Winter Honeybaby squash: This plant is productive and is compact. The vines grow to 2-3 feet in a semi-bush habit and would be great for a container garden. The squashes are short and wide and are meatier than most squash. The taste was described as sweet and nutty, and it was recommended to be used steamed, baked or made into soups and stews.

Chef’s Choice Yellow tomato: This is a beefsteak type indeterminate (produces all season) tomato with a nice yellow color and a great taste. The plant is productive, with 30 or more 10-ounce tomatoes on a 5-foot vine per season. It has multiple disease resistances.

Patio Choice Yellow tomato: This tomato is a compact determinate (produces one crop) cherry tomato; the vines grow to 18 inches and are ideal for containers or limited-space gardens. The plant is said to be productive, with more than 100 fruit per season, and having a favorable mild flavor. This tomato would work in a hanging basket and you would have the fruit at your finger-tips.

There are other vegetables and a host of ornamentals in this group of AAS winners; consider looking them over.

Garden tips

·       Most bedding plants, summer-flowering bulbs and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low 60s. The Oklahoma Mesonet website has information about soil temperatures.

·       Harden off transplants outside in partial protection from sun and wind prior to planting.

·       Don’t plant tomato sprouts too early. The soil temperature is key and should be above 60 degrees before planting. If the soil is too cool, the plants will sit there and not grow. Remove the blossoms from any tomato plant at the time of planting, it needs roots before making tomatoes.