Winterizing Warm Season Grasses is a No No

Question: The lawn care company recently applied an application of “winterizer” fertilizer to my Bermuda grass. Do you recommend winterizer fertilizer on warm season grasses?

Answer: If this is a well established lawn it is doubtful you need a fall application of fertilizer unless a soil test indicated a low level of potassium. Unfortunately, there are many products on the market sold as winterizer fertilizer. Cool season grasses such as fescue do most of their growing in the fall and spring and they need nitrogen to grow. However, many of these products are also used on warm season grass. Fall nitrogen application can be damaging to warm season grasses. Instead of increasing the cold hardiness, the opposite effect results. A warm fall will lead to continued vegetative growth which sets the plants up for cold damage. Check with your lawn care company and ask for the analysis of the fertilizer used. If the first number is 5% or below, it probably won’t hurt but it would be better if no nitrogen is applied to Bermuda and other warm season grasses after August.

I would suggest you have your soil tested to see if you need potassium or not. If you fertilize during the summer months it is very doubtful extra potassium in the fall will provide any benefit. However, if you do apply fall fertilizer, always apply it onto dry foliage to reduce the likelihood of salt burn.

A soil test provides a wealth of information and can be done for only $7 in Alabama and many state Extension offices offer similar services. Fall is a great time to test the soil because the lab is not as busy and if you need lime you have time to get it out on the lawn before spring growth starts. The lime will slowly move into the soil with winter rains and the pH will gradually rise in time for the first spring growth spurt. Once you receive your test results you may want to contact your local Extension office to talk with a horticulturist about your test results.
I have seen many test results that indicated an excessively high level of phosphorus and potassium. Phosphorus does not leach from the soil very quickly and it can build up to the point that no phosphorus will be needed for many years. Potassium can become so high that it interferes with the uptake of other elements such as magnesium and can result in a lighter green turf color. Also, be aware that an excessively high rate of potassium fertilizer can cause foliar burn.

Fall Is For Planting

Question: I am planning on planting some trees and shrubs this fall and would appreciate some planting tips to insure success.

Answer: Most of the time I get questions after newly planted trees and shrubs start to die, but I much prefer offering pre-planting advice to avoid problems.

Fall is the best time to plant most perennial plants including trees and shrubs and even most herbaceous perennials. The keys to success start even before planting perennials in the ground. It is always advisable to do a little research on the front end. There are some important questions you should answer before planting anything. One, are the plants I have in mind adapted to our climate? And I don’t mean adapted just to cold, but also to heat which is often as important as cold in our area. Two, will the plants tolerate the drainage within my soil? Poor drainage causes more plant death in heavy clay soils than drought does. Third, is the site chosen adequate for continued growth of the chosen plants? You should always think about the mature size when choosing the planting location and plant material.

The actual planting process will determine in large part the future growth and possibly whether or not a plant survives at all. There are at least two myths about planting woody plants that reduce your chance of success.

The first myth is that you should amend the planting hole with loose organic matter. If you have a lot of clay in your soil you should not use any organic soil amendments. There are several potential problems with adding organic matter and they all revolve around water. If organic matter is added to a hole surrounded by heavy clay soil, the water movement is drastically altered. You will have one of two problems. Either the water will not move out of the hole after rainfall, causing a bathtub effect, or the organic matter will dry and not re-wet well. Both of these scenarios will lead to root death. Plant wilting is not a good indicator of whether the soil is too wet or too dry because drought and excessive water both cause wilt.

The second myth is that you should not disturb the root ball coming out of the container. This myth relates to the previous myth, but needs some further explanation. Most plants are grown in containers at the nursery in a very light ground pine bark mix. This mix is great for growing shrubs and trees in the nursery but can present terrible problems in the landscape. If this loose bark is allowed to remain intact, the water movement issues described above still apply, with the added problem of air pocket development around the roots as the bark decomposes. Therefore, it is best to gently wash most of the loose bark material off the plant until it is, for all practical purposes, a bare root plant. This may involve pulling the roots out if they have started winding around the root ball. If necessary you can prune or slice these roots to help make this job easier, but try to leave as many roots intact as possible.

The planting hole should be shallow and wide. The depth only needs to be as deep as the root ball, but the hole should be two to three times the width of the longest lateral roots. Look for the uppermost lateral root to determine the planting depth. This lateral root should be at grade or slightly above the surrounding soil grade. Make a small ring of raised soil to hold water near where the outermost roots extend. Keep this area moist at all times for the first several weeks and then gradually decrease watering frequency and increase watering depth to encourage deeper rooting. Mulching the root area can give you a false sense of security about whether the plant has adequate water. It is very important to check the root area frequently to avoid drying. Do not apply mulch more than a couple inches thick.

A couple other post plant care tips are to keep the area around trees and shrubs weed and grass free, widening the weed free area as the plant grows. Also, avoid using weed whackers or mowers near the plant base.

Sweet Tea Olive

Fall is a great time to visit the Birmingham Botanical Gardens for many reasons but the fragrance coming from sweet tea olives is highest on my list. Tea olives are in the plant Genus Osmanthus which comes from the Greek and means “fragrant (osma) flower (anthus)” and it certainly lives up to the name. Tea olive, as the name indicates, belongs to the Olive Family (Oleaceae) along with numerous jasmines which are also very fragrant. The usually white blooms are small and not extremely showy and I am not surprised you could not tell where the fragrance originated. Even though individual blooms are small some cultivars have clusters large enough to add some floral interest. Tea olives are very nice evergreen shrubs with holly like foliage. You can easily tell the two apart even when not in bloom by looking at the leaf arrangement. Hollies have leaves arranged alternately down the stem and tea olives have an opposite arrangement.

There is a large planting of Osmanthus x fortunei 'Fruitlandii' at the BBG that makes a wonderful screen planting that is a pleasure to walk near. The mature height of tea olives may vary from six to thirty feet depending on the species and cultivar. I lived in Mobile in the past where the “fragrant tea olive” Osmanthus fragrans was the most commonly planted species. It is less cold tolerant but will survive in central (possibly north) Alabama in a protected micro-climate. It would be best to locate this plant on the south or southwest side of a structure. Much like camellias the main risk from cold is the rapid freezing and thawing action that is worse with a morning sun exposure. As the name seems to indicate it is the most fragrant of all the tea olives and therefore may be worth the risk of occasional cold damage. It also has the longest bloom period with blooms possible in every month with the letter “R” included.

In general all the tea olives will grow in full sun to part shade but in the central southeastern United States I would suggest a site with a break from the afternoon sun. Once established they are fairly drought tolerant but it may take a couple years to become established. Fall is a great time to plant and will require less care than spring or summer plantings. Choose a well drained area with slightly acidic soil for best results.

Tea olives are really quite easy to care for once established and have very few pest problems. If pest problems do occur it is probably due to stress from poor soil conditions or drought. Scale insects may flare up from time to time but can be controlled with horticultural oil sprays. Minimal pruning is needed unless they get too large. If you do prune them do so in the late winter to avoid removing the flower buds which form on the new growth each spring and summer. The exception to this rule would be the Delavay tea olive (Osmanthus delavayi) and our native Devilwood (Osmanthus americanus) which bloom in the spring and should be pruned just after blooming like other spring blooming plants.

Devilwood is the only native tea olive and is native to swamps and stream banks in the southern US including south Alabama. The name comes from the extremely hard wood which is a “devil” to split and work. The leaves are larger and less holly like than other tea olives. Like other tea olives the flowers are quite fragrant but they occur in early spring on last year’s growth. This native plant is more tolerant of wet soil conditions but is adaptable to most Alabama soils. It would be a great choice for a rain garden because it tolerates frequent flooding and can take the drier times between rain events.

Regardless of which tea olive you plant you are sure to be enchanted by the sweet aroma they produce and yes they can be used in tea.

Pruning Encore Azaleas

Many people ask how to prune Encore Azaleas and a picture is worth a 1000 words - so take a look.

Wooly Bugger of a Problem

Question: There is a tree in our yard that has rough warty bark and makes a small fruit about the size of a cherry. The problem is it is dripping a sticky substance on everything underneath its limbs. Do you have any idea what tree this is and what might be the problem?

Answer: The tree is probably a native hackberry or sugarberry tree, but the fuzzy white pest causing the sticky mess is not native. The pest is called the Asian Wooly Hackberry aphid and was first detected in North America on hackberry trees in Georgia in 1996 and in Alabama in 1998. It is not a severe problem every year, but it appears to be a problem this year. The aphid appears to be restricted to native hackberries or their relatives. Although the trees seem to survive the pest flair ups fine, the aphids produce large quantities of the sticky substance called honeydew. As you observed, this creates a sticky mess and promotes the growth of black sooty mold on leaves and on surfaces beneath infested trees. In August and September it can look like a mini snow storm near these trees because the aphids look like cotton fuzz balls. Although this tree is a very tough tree for urban environments, the honeydew can be an annoying problem in residential and business districts where the tree may be used to shade parking lots, walkways or patios.

Some municipalities out west have been treating all hackberry trees in parks and parkway strips with a systemic insecticide called imidacloprid, which is an effective, but relatively expensive insecticide. Researchers at the University of California have had good results with this insecticide even with rates as low as one eighth of the label recommendations. Since it is a fairly expensive product you might try these lower rates and just provide adequate water to make certain what you apply is not wasted. Imidacloprid can provide season long control and can be applied during the growing season after you notice an early infestation in the spring. Treatments are applied as a systemic insecticide, meaning that the product is taken up by the roots of the plant and spreads through all the tissues of the plant. The material may be mixed in a bucket of water and poured around the trunk. It is too late to treat trees now and it won’t be long before the leaves fall off anyway. Just to play it safe don’t use this product near edible plants since it is taken up by plant roots.

The fruit is a favorite fall treat of many birds and other wildlife. This is another reason to use the lowest possible effective rate of insecticides so that the pesticide will be out of the plant by fruiting time. Since there is no research to tell us if the chemical is totally gone by harvest time, I would suggest you avoid eating the fruit.

I talked with the director of the Plant Diagnostic Lab here at the Hanna Environmental Center, Dr. Jim Jacobi and he said “the wooly hackberry aphid does not cause appreciable damage to tree health but from time to time can be quite a nuisance. I would not plant this tree in an area near a parking area or patio, but it can still be used as a specimen tree in a natural area or at the fringes of your property where it won’t cause a mess and can still provide food for wildlife and act as a host plant for at least three species of butterflies that develop on the foliage.”
For more information visit the following web address: http://msucares.com/ and search for Wooly Hackberry Aphid. A great detailed article will be the first link that pops up.

Central South Native Plant Conference

Birmingham Botanical Gardens will host the Central South Native Plant Conference at which I have a small speaking part.

Every three years gardeners, landscape architects, and plant enthusiasts of all kinds are treated to one of the most extensive seminars in the nation, the Central South Native Plant Conference. The symposium, whose theme is “Tough Native Habitats”, will be hosted by Birmingham Botanical Gardens October 17 and 18.

Held about every 3 years since 1989, the conference “is a place for people to learn and to share their knowledge about our regional biological heritage” says program chair Jan Midgley. The focus of the weekend is native plants that call Alabama home. Birmingham Botanical Gardens plays host the 2008 conference, whose goal is to foster awareness, appreciation and increased usage of plants native to the Southeast.

Highlights include an outstanding line up of Southeastern native (and invasive) plant experts in a variety of lectures, break-out sessions, field trips and tours. From novice to expert, everyone is welcome but you need to pre-register. The complete program and registration information is available at www.bbgardens.org . You may also contact Shelly Busby, Special Events Coordinator at Birmingham Botanical Gardens for tickets or with any questions by calling her at 205-414-3965.

Ant Invasion

Question: My house is being invaded by ants. We do not leave food stuff or dirty dishes out so what is causing this ant explosion?

Answer: When outdoor temperatures get hotter and conditions get drier ant problems get markedly worse. The ants are most likely Argentine ants but during an extreme drought fire ants may also come indoors. Both travel in trails into kitchens, offices and bathrooms searching for food and/or water. Even if you are super clean they may come indoors in search of water.
Argentine ants which are small, just 1/8 inch long are very consistent in size. They are native to South America. They were accidentally introduced into the United States more than 100 years ago in New Orleans coffee shipments. Fire ants are likewise South American natives and came in sometime later through Mobile Alabama. Fire ants will often be quite variable in size from 1/16 inch to 1/4 inch long, they have reddish brown bodies and black abdomens and they also bite!
Entomologists say you can reduce your chances of having ants in your home but even the cleanest homes may become infested. To discourage them, rinse all drink cans before placing them into the garbage or recycling bin and empty garbage containers often. And, don't leave any food or drinks out for any length of time. Argentine ants love sugar and will show up to dine on it, literally by the thousands, overnight.
For Argentine ants most experts don't recommend using contact insect killers. These products may make you feel better because you can watch the suckers die in real time but you'll never get rid of them all. For long term controls of both types of ants you have to kill the queen or queens. For Argentine ants the ant bait stations or gels work the best. They don’t give you that immediate satisfaction of a contact killer but the results are much longer lasting.
If you have fire ants the control should involve a little more effort in finding the source. Treating outside will help control ants foraging inside from outdoor colonies. Although unlikely it is possible the ants are nesting in a wall. In this case, a contact insecticide should be used at the nest source and it may require assistance from a professional pest control operator to locate the nest. More likely, the fire ants are in an outdoor mound and foraging for food or water indoors. You might say they live in the suburbs and commute in to work. If you decide to treat indoors make sure the product you select is labeled for use indoors. Read and follow the directions on the product label for best results. Be sure to keep products away from children and pets. Again, eliminating the outdoor colonies will be critical to ridding your home of this menacing pest.

For more information visit the newest nationwide Extension website: www.extension.org and check out the fire ant portion of the site. This site has a wealth of information that you can trust has been well researched and is very up to date.