Thursday, December 06, 2007
Clean violets to remove indoor pests
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
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Q: Please help. I have been pleased by the colorful blooms produced by the African Violets that I have growing under timer lights. But, since this past fall, the violet crowns get real hard, plus the leaves are tiny and do not grow. I bought one new African Violet to put under my grow lights, thinking that the problem was that my old violets were just getting too old. However, the new African Violet eventually got the same way that the others were. What causes this and what can I do about it in order to have healthy, blooming violets again?
A: You have described typical damage to African Violets caused by the very tiny sucking pest called “cyclamen mite.” As you discovered, do not place new violets close to infested ones. In particular, do not let the leaves of any one African Violet touch the leaves of neighboring violets.
The first step in treating infested violets is to trim off all badly injured plant parts, as far as practical. Readers might recognize this as an important first step in getting rid of various pests on indoor plants.
Then, immerse infested plants, pot and all, for 15 minutes in clear water held at 110 degrees F. Violets have fuzzy leaves that do not like getting wet in cold water, so do this procedure in a warm room so that the wet leaves will dry quickly after submersion. Your purpose will be for water droplets to evaporate before that water in the drops becomes cold and violet leaves become spotted.
Finally, spread out your hopefully clean violets. Monitor their condition each day for 3 weeks or longer to see if some cyclamen mite adults or eggs did not drown or suffocate, and new symptoms are showing up. If any infestation continues, repeat the warm water treatment.
Q: Our blackberry plants survived the summer drought and made long branches that bent over and took root where the branches touched soil. Can these be cut and planted as new plants? Also, this past growing season, our tomatoes had a hard core that extended nearly all the way through. Why did they have this, and how do I prevent this now in the off season before next year’s garden?
A: Black raspberries root themselves as you witnessed in a method called “tip layering.” Yes, the tips that have rooted by themselves can be cut, each giving you a new blackberry plant that can be dug and transplanted in late winter while still dormant but after the soil temperature has begun to rise.
Tomato plants produce those firm masses in their core as a result of some kind of adverse growing condition. The major garden stress producer this past growing season in much of this country was the hot, humid but dry weather. You know the care that you gave to your tomatoes, so the stressor that caused your tomatoes to have hard cores could have been caused by some other adversity.
The most effective way to prevent this from occurring next year would be to do everything during the off season to prevent or reduce adverse conditions on your plants that can occur from spring planting time through fall frost. A great suggestion now is to save winter and spring precipitation water coming from your gutters in plastic jugs or an old-fashioned rain barrel.
Another job for the off season, think back to this last tomato patch and your garden diary to see if you grew a tomato variety that produced fewer or smaller hard cores than other varieties. If so, plan to grow more of that variety in 2008 since it could safely be assumed that this variety is less affected by stressors than others.
Q: I loved the yellow fall color of ginkgo trees planted in a Virginia public landscaped area this fall. However, I remember the terrible smell that was in the area of one of the ginkgo trees. A friend told me that this was the smell of the ginkgo fruits. Do all ginkgo trees produce that stink? Can something be done to prevent that smell?
A: That stink comes from the fruits produced by female ginkgo trees. Ginkgo trees are like American Hollies in that they have separate male and female plants. The remedy to this is to plant only male trees, since they don’t make fruits. However, it has been impossible to easily and accurately tell the sex of ginkgo trees until they are about 20 years old. Ginkgoes don’t produce flowers until that age.
I don’t know of a spray that can be applied to make a female ginkgo tree unfertile.
A sure-fire way to avoid ginkgo fruits is to start your own ginkgoes by rooting softwood cuttings from branch ends of 30 plus year-old male ginkgo tree in midsummer. These cuttings should take root quite well, but ginkgo trees grow slowly, so it will be years before you will enjoy the beauty of your outstanding tree.
