Bamboo Control

Question: How do I control run away bamboo in my yard?

Answer:
Bamboo is one of the most difficult invasive plants to control once established. The wrong type bamboo can take over landscapes, stream banks, and woodlands.

There are many species of bamboo sold in the nursery trade, some are more invasive than others. Creeping types are, as a rule, very invasive once established. There are clump-type bamboos that spread at a much slower rate. For most homeowners this is the most responsible choice. You may avoid control problems down the road and your neighbors won’t be so upset. These clump-type bamboos can be removed by digging up the offending plants. Unfortunately, some of the more popular types of bamboo sold in the nursery industry are the more invasive, spreading types. These plants spread by thick, tough, underground stems (rhizomes). The rhizomes are resilient to tough environmental conditions and most herbicides.

To control such aggressive plants you must eradicate or contain the entire infestation. Treating only a part of the infestation will be doomed to failure because bamboo can re-establish rapidly. Also, bamboo control programs will require an intensive control strategy over several years.

Containment of creeping types of bamboo is possible, because the rhizomes are typically fairly shallow (less than one foot deep in the soil), but difficult because they can grow over the top of barriers. Barriers made of concrete, metal, plastic, or pressure-treated wood should be installed at least 18 inches deep. Inspect the barrier once or twice a year and remove any rhizomes that are visible.

To control, start with physically removing as much of the rhizome and root mass as possible. It will be impossible to remove all pieces; therefore, follow-up treatment with herbicides will generally be required. Few herbicides are effective on bamboo. The only treatment regime that has been proven to work are winter applications of diclobenil(Casoron or Barrier) combined with summer spot sprays with glyphosate (Roundup). Diclobenil will kill many of the rhizomes and prevent others from re-establishing through early summer. After that time new sprouts will emerge and must be controlled to prevent re-establishment. Reapply glyphosate whenever new growth is present. It will take at least two years of this regime to get good control. In that time you will not be able to plant herbaceous ornamentals, hemlocks, or many other shrubs in that area because diclobenil can kill these ornamental species. If the bamboo is growing in plant beds where these herbicides cannot be used, remember bamboo is a grass and can be suppressed with selective grass controlling herbicides. Always check chemical labels to make certain the product can be used as you intend.

A non-chemical option is to put the entire infestation into turf for several years. Bamboo does not tolerate frequent mowing. Remember, regardless of which method of control you choose, an intensive effort over multiple years will be required to completely eradicate bamboo. Therefore, spend a little extra time researching which ornamental bamboos are best for your yard.

Much of the information in this blog came from an NC State article by Dr. Joseph C. Neal, Weed Scientist Department of Horticultural Science. You may also read another good publication on this subject from the University of Florida by Jason Ferrell, Mark Czarnota, and Ken Langeland (who took the picture above)

Stevia

Question: My new year’s resolution was to loose some weight and I have heard there is an herb that can be used as a sugar substitute. Since sweets are my weakness I am looking for a natural sugar substitute. Do you know what the name of this herb is and how can I grow my own sugar substitute?

Answer: There have been few botanical discoveries quite as dramatic as the realization that the leaves of a species of herb called, Stevia rebaudiana, are intensely sweet. Stevia plants are perennial plants native to Paraguay that include over 150 different species. However, this particular species is an anomaly, since none of the other species in this North and South American genus produce these sweet compounds at high concentrations. Stevia sometimes called “sweet leaf or candyleaf” is considered by the U.S. Food and Drug Administration to be an unapproved food additive. It is approved by the FDA only as a dietary supplement. There is conflicting research on the safety of this herb and you should research carefully before using any herbal product.
Because they are commercially unprofitable, relatively few highly sweet plant components have been developed as sugar substitutes. However, due to the interest in natural products, the discovery that this stevia plant has naturally occurring sweetness has attracted great interest. Stevia and stevioside, an extract of stevia, have a menthol-like, bitter aftertaste that limits their usefulness. However, they have been used for years as sweeteners in South America, Asia, Japan, China and some European countries.
For many centuries native Paraguayans have used stevia as a sweetener in herbal and medicinal teas. As mentioned, stevia cannot be sold and advertised as a sweetener but it is available as stevioside extract and can be purchased at most health food stores. The first thing to remember is that stevia is sweet but not exactly like sugar. All this sweetness comes from the leaves of a rather homely little plant that at maturity can be up to 18 inches tall and as wide. It’s a perennial herb that won’t tolerate freezing temperatures. Therefore, grow it as a houseplant or treat it as a tender annual that’s set out after all danger of frost is past. Bear in mind that temperatures can affect the sweetness. The stevia leaves will be sweeter as the temperatures increase throughout the summer.
Stevia is can be grown from seed, but is more easily rooted or it may be purchased as a small plant in the herb or perennial section of the garden center. Your small plants will start slow, much like a pepper plant or okra which requires hot weather to grow well. They need a good rich soil, full sun, warm air, and just enough water to keep the growing medium evenly moist. They’ll be quick to drown if you over water and equally quick to die if you let the soil dry out completely. If you are more interested in the sweet leaves you should remove the small white flowers that appear in summer. They are heavy users of nutrients and should be fertilized regularly or use a slow release fertilizer at planting. They may occasionally be attacked by aphids, mealy bugs, and spider mites, so keep an eye peeled. If you catch the pest early a strong stream of water may be all that is needed or use a little insecticidal soap as directed on the label.
Use stevia leaves fresh or dry them for storage by placing them in single layers between paper towels set in a warm place for a week or so or dry them in a dehydrator. Then use a spice grinder to reduce them to powder. It may not solve your sweet tooth problem but you are bound to burn a few calories while working in the garden.

Note: See this publication from which much of this information was derived. Thanks to Georgia Jones, Extension Food Specialist at the University of Nebraska.

Drip Irrigation

Question: I want to install a landscape at my new home but am very worried about the water shortage. What tips can you give to increase my chance of success?

Answer: The first suggestion would be to plant as soon as possible. In our area we can plant woody plants all winter if the ground is not frozen. The plant roots will start to grow and establish before the plant top growth occurs and before the stress of a hot summer.

Second, I would encourage you to consider using a low volume irrigation system. Low volume irrigation unlike sprinklers puts the water in a small area near the plant. Sprinklers are very wasteful because they water the entire surface area and much of the water either runs off or evaporates. Low volume methods work by placing emitters in a flexible tube near the base of newly planted trees and shrubs. (picture at right is from the University of Texas publication on "Low Volume Irrigation")

The primary design goal of a low volume system is to apply water to a uniform soil depth. Water is delivered at or below the surface of the planted area exactly where it is needed. For new landscapes the emitter should be placed directly over the edge of the root ball of the newly installed plants. This will keep the root ball moist while encouraging new roots to develop in the native soil. For larger plants you may need two or more emitters to insure the root ball maintains adequate moisture.

These systems are not difficult to install and remind me of playing with tinker toys as a kid. The most critical part of installation is making sure you reduce the pressure before the water enters the drip tubes and provide a screen filter in-line to avoid stopping up the small holes in the emitters. It is very important to periodically check the emitters to make sure they do not get stopped up. Unlike sprinklers which are highly visible you can’t really tell if emitters are working unless you inspect them while they are operating.

I have often been asked why can’t I just punch or drill a small hole in a water line near the plant rather than buying emitters. The answer is simple. These small holes would not distribute the water evenly, the water would come out too fast, and the hole would get larger over time. Emitters are designed to put out very slowly at rates from ½ to up to 2 gallons per hour. If your soil is a very heavy clay soil you would want a very low rate emitter and if it is sandy you could use the higher rates. If you use a high rate emitter on a heavy or hard soil the water will pool on the surface and run off the target area.

I know many municipalities tell their customers to do hand watering only during times of water shortages but low volume drip irrigation is even more water conserving then hand watering. Generally speaking when people do hand watering on new plants they water a larger area than necessary, water is applied too quickly causing runoff, and some water evaporates before reaching the ground. Also, who’s going to know if the water is on if it is below the surface. I am not encouraging wasteful use of water but I believe this is even more water conserving than hand watering and I would not feel the least bit guilty for using this method in lieu of hand watering. Just make sure you are using a timer so that the system only runs a prescribed amount of time. I made the mistake of leaving mine running without a timer several years ago and floated my plants out of the ground after a couple days. To learn more you may watch a short training video for gardeners at Texas Earth Kind web site and choose the "Low Volume Irrigation" tab.

Poinsettia Care

Question: I am planning a trip away from home for about a week and want to keep my poinsettias looking good enough for a New Years party. What suggestions do you have?

Answer: The first thing to do is to make sure the plants have a relatively long display live remaining. The best way to tell this is to look at the blooms or bloom buds. As seen in the photo to the right the blooms are in the center of the colorful bracts. You should choose plants that have either unopened green buds or slightly opened yellow blooms. If the blooms are dead or dying the plant does not have a long color show remaining.

Your poinsettia can add beauty to your home throughout the holiday season if you place it in an optimal location for its needs. Poinsettia do best in bright, but not direct, sunlight. Put the plant near a sunny window but not in direct sunlight. Direct sunlight could discolor the bracts. On the other hand, low light can cause the plant to lose some of its leaves.

Poinsettias will not tolerate moisture extremes. Do not keep the potting mix too wet or too dry. If allowed to dry out too much, the plant will wilt and drop its leaves. Conversely, don’t allow the plant to remain in standing water. This could result in root rot, which will cause the plant to decline.

Poinsettias do not last long when exposed to extremes in temperature, particularly in drafty locations. This can cause overall plant decline and leaf drop. Keep the plant away from heat vents and outside doors or windows. Try to maintain the temperature at no higher than 70 degrees F. If possible, keep the plant with other plants or set the container in a gravel-filled pan half-filled with water. Doing this will keep the humidity a little higher around the plant in an otherwise dry, winter home. Since you are leaving I would suggest turning your heat down to 55 or 60 degrees F. and this cooler temperature will preserve the color life considerably.

For more information and after Christmas care see the ACES publication:
Consumer Poinsettia Care

Climate Change

I was recently visiting a friends home and we started talking about “Climate Change” and he said, “I want you to read something out of the 1939 Yearbook of Agriculture”. If you remember your history you will recall that this was the time of the “Dust Bowl” in the southern plains. The 1939 Yearbook of Agriculture talked about this disaster as well as the severe flooding in other parts of the country. In general it was a decade of extremes of many kinds. One very interesting notation made was that there was much speculation at the time that the changes were possibly permanent and that they were influenced by mans activities. There is no doubt the wind erosion was due in large part to poor tillage and agricultural practices but the author was very skeptical about climate behavior being a result of human activity.

A recent report also exhibits some skepticism about many of the most used climate models and their reliability in predicting past climate changes. The authors of this study wonder if these models that do a poor job of predicting past changes can be relied upon to predict future changes. This research was published online in the Royal Meteorological Society's International Journal of Climatology.

"The usual discussion is whether the climate model forecasts of Earth's climate 100 years or so into the future are realistic," said the lead author, Dr. David H. Douglass from the University of Rochester. "Here we have something more fundamental: Can the models accurately explain the climate from the recent past? "It seems that the answer is no."

Scientists from Rochester, the University of Alabama in Huntsville (UAH) and the University of Virginia compared the climate change "forecasts" from the 22 most widely-cited global circulation models with tropical temperature data collected by surface, satellite and balloon sensors. The models predicted that the lower atmosphere should warm significantly more than it actually did.

"Models are very consistent in forecasting a significant difference between climate trends at the surface and in the troposphere, the layer of atmosphere between the surface and the stratosphere," said Dr. John Christy, director of UAH's Earth System Science Center. "The models forecast that the troposphere should be warming more than the surface and that this trend should be especially pronounced in the tropics.

"When we look at actual climate data, however, we do not see accelerated warming in the tropical troposphere. Instead, the lower and middle atmosphere are warming the same or less than the surface. For those layers of the atmosphere, the warming trend we see in the tropics is typically less than half of what the models forecast."

Wiley-Blackwell (2007, December 12). New Study Increases Concerns About Climate Model Reliability. ScienceDaily. Retrieved December 17, 2007, from http://www.sciencedaily.com/releases/2007/12/071211101623.htm

Dust bowl picture from: A black blizzard over Prowers Co., Colorado, 1937. (Western History Collection, University of Oklahoma)

Question: I used a live Christmas tree this year and I want to plant it in the landscape. The plant is an Arizona Cypress called ‘Carolina Sapphire’. How large will this tree grow to at maturity and will it grow in our climate?

Answer: Balled-and-burlapped or container-grown Christmas trees can be planted out as landscape trees after Christmas. The sooner you can get it outside and in the ground the better. If you can not plant it right away at least move it out of doors to the cooler environment and keep it well watered. With care and planning, your Christmas tree will serve as a living memory for many years. I used a white pine the first year we lived in our current home and it is about 10 years old and still growing well. On the other hand my mother used a Norway Spruce many years ago and it struggled along for several years before dying at a rather young age. Needless to say some Christmas trees are more suitable to our climate than others. You may have problems with Norway Spruce, Hemlock and Firs but have good success with the Arizona Cypress you mentioned, White Pine, Virginia Pine, Leyland Cypress, Eastern Red Cedar, and Japanese Cedar.

When I lived in Mobile my home was next door to a large wholesale nursery. One December morning I was admiring some of their pyramidal shaped Foster hollies. I told the owner, Tom Dodd III that I thought it would make a great Christmas tree so he loaned it to me for the month and it did make a very nice tree and was no worse for the wear when I returned it in January. I got the idea from my father-in-law who always has a very unusual Christmas tree. A couple years ago he used a six foot tall Satsuma orange tree loaded with fruit. Another year he used a pear tree that was decorated with pears and pairs. For instance, he had a picture of a couple famous doctors and they of course were a “pair-a-docs”(paradox). All his Christmas quests enjoyed the challenge of figuring out what his ornaments represented and each year there is an anticipation of what kind of tree he will come up with.

Back to the original question you asked about Arizona Cypress. You can expect this plant to reach 20 to 30 feet tall, 8 feet wide. It has a very rapid growth rate while young. Plant it in full sun and a well-drained soil. It thrives in hot and dry conditions once established but needs supplemental water the first year. Make sure you remove the bag if it is in a synthetic burlap bag. If you are not sure I would play it safe and take the bag off completely. If it is in a container take it out and bump it on the ground a few times to get off a lot of the loose bark. Plant at the same depth it was growing because setting this plant to deep can be deadly because it needs good drainage.

Think ahead for good tomato crop

Last year was a bad year for gardening in many ways. Tomatoes were particularly hard hit in the early season by a disease that rears it's head from time to time called Tomato Spotted Wilt Virus (TSWV). This virus is usually spread by very small insects called thrips. Infected tomato plants become stunted and often die. Initially, leaves in the terminal part of the plant stop growing, become distorted, and turn pale green. In young leaves, veins thicken and turn purple, causing the leaves to appear bronze. Dead looking spots, or ring spots, are frequently present on infected leaves and stems often have purplish-brown streaks. Fruit, infected with the virus, may exhibit numerous ringspots and blotches and may become distorted if infected when immature.

Currently, there are no real effective chemical controls for this disease in the garden. Keeping the area around the garden as weed free as possible may help by reducing the over wintering host plants. Destroying infected plants as soon as symptoms appear may also reduce spread of the disease. There has been some research that shows a benefit from using an ultraviolet (UV) reflective mulch. UV-reflective mulches are available commercially in small packages for home owners. It is basically plastic mulch with an aluminum foil appearance. It works by repelling the thrips that spread the disease. Lastly, there are some TSWV resistant varieties on the market but they will be difficult to find. This is the reason I suggest you start thinking about your tomatoes now.

I suggest you either contact your garden center and ask them if they plan to have the resistant varieties this year and if not you may want to grow your own transpalnts. I just returned from the Deep South Fruit and Vegetable conference in Mobile, Alabama where Dr. Jimmy Boudreaux from LSU discussed this problem. He mentioned some varieties with good resistance to grow. Previously the one I have grown is Amelia which is a good choice. He mentioned a variety called Bella Rosa that sounds real good. He compared the flavor with a favorite of mine called Celebrity. Celebrity is a great tasting tomato and very popular everywhere it is grown. A couple other resistant varieties you may find available are Crista and RedLine.