Thursday, May 01, 2008
Pampas grass should be cut now
John Arbogast
Landscape consultant John Arbogast answers your questions every Thursday. Send questions about your lawn, garden, plants, or insects to:
Dear John
5102 Greenfield St. SW
Roanoke, Va. 24018
Or send an e-mail. Answers will be given only in this column. Please don't send pictures or samples.
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Q: I live in New Mexico (Central); I want to cut back Pampas Grass now. Is it too late to do so? Also, can I cut the flower stalks?
A: I don’t have any knowledge about your climate there in central New Mexico. My opinion is that it’s not too late now to cut back Pampas Grass. However, the location of your cuts should be just above the top of new Pampas Grass shoots, which should not be cut through or damaged.
Before you cut, look carefully at the lower portion of your Pampas Grass and find the tips of new ornamental grass blades. Cut just above the new tips. Pampas Grass tips will turn brown if cut or injured at this time since new tips are soft and moist. Even though a pruning cut is smooth and straight, the moist blade tissue dries out quickly when exposed to air.
Last year’s Pampas Grass flower stalks can be cut now, but caution is advised in making low cuts to avoid soft new shoot injuries as mentioned. I don’t know how low your stalk cuts can be made, but I do know that flower/seed head stalks that are old are brittle and weak.
Q: My Foster Holly needs help now here in west-central Virginia. The holly has probably been in its location for 20 to 25 years. It is about 25 feet tall. Its foliage has become thin and the color is a lighter green than it should be. There are a lot of yellow leaves, especially in the lower portion of the holly. The upper portion of the tree has only sparse foliage. You can see the forked trunk in the center of the holly. It has berries throughout, though. The Foster Holly was planted about 4 or 5 feet away from the house wall. I looked and did not see any pests or diseases on the holly. What should I do to make the holly look better again? I do want to save it.
A: It sounds like your Foster Holly is suffering from environmental problems, a term used to describe stressors caused by the specific site and age of a given plant. Being that close to the house wall, I’m thinking that the poor condition could be the result of limited air circulation and maybe too much humidity or dampness right in that area. To try to improve the holly’s landscape appearance, I’d suggest improving air circulation in the area, raking under the tree as needed, cutting the tips of side limbs and the trunk tip back by around 18 inches now in the spring to stimulate new dense growth, and fertilizing now to improve leaf color.
Use a narrow rake to remove the accumulation of old fallen leaves, plant debris including berries, and old mulch from under the Foster Holly’s canopy. This accumulation of old organic matter can be placed in layers to provide mostly carbon to an active compost pile. Heat from the active compost process works to kill living pathogens and pests that might be present. Fresh mulch is probably not needed under the holly at this time so that the soil can breathe.
Cutting back your Foster Holly now during the time of normal vegetative bud growth emergence will force the holly to produce new leaves. This suggestion is aimed at improving the density of the holly. However, the plant will probably look brown and bare for a growing season or longer following this heavy pruning as new greenery fills in.
Applying nutrients now to your Foster Holly should improve the green color of existing leaves plus enhance recovery from pruning. Use a commercially available tree and shrub fertilizer. Follow the instructions given in order to use the correct amount as well as to insure availability of the nutrients to the holly. A “soluble” fertilizer, which is the name of the type that is designed to be mixable in water, might provide nutrients more quickly than a granular fertilizer. Keep in mind, though, that all nutrients need repeated waterings once per dry week to wash them into the complete root depth.
Q: How important is it to rotate the location of vegetable plants in a small vegetable garden with limited space?
A: It's very important, even in a small vegetable garden, particularly if past garden crops have had diseases or pests, and possibly infected plant debris has been allowed to fall off where it has remained among organic garden mulches. Pest eggs and disease vectors will survive even a moderate winter and will be ready to infect new plants of the same type if the right environmental conditions occur.
Resistant vegetable varieties will help reduce susceptibility in small areas, but there’s no guarantee.
