Gardening with Tracey Fitzgibbon
Q: The flower buds of my potted geranium aren’t blooming well. Some of them look like they have holes drilled into them! What’s going on with my plants? — L.G., West Side
A: I’m confident, from your description, that your geraniums are hosting several budworms. Unless you treat for them they’ll continue to eat the flowers, leaving you nothing to enjoy. A pesticide known as Bt will be the safest and very effective way to combat these bugs. Bacillus thuringiensis — Bt — when sprayed on the plant will be ingested by your munching caterpillars and upset their insides to the point they don’t eat anymore and, in turn, die. It’s the safest insecticide I know of to combat budworms. You will want to mix up only what you will apply each time as it does not have a long shelf life. Also the Bt loses its effectiveness when exposed to sunlight for extended periods of time, so spraying at dusk is the ticket. The added benefit of spraying at dusk is that’s when the budworm is at its most active, so they’ll consume more of the pesticide. I would suggest that you sacrifice any and all of the blooms your geraniums are wearing, from young bud clusters to older nearly spent blooms, for the time being. Then, spray twice, in two- to three-day intervals, so any budworms that are hiding on your geraniums are affected. With timed applications of the Bt your geraniums should rebound easily growing more budworm free blooms for you to enjoy as the season progresses. If you have any petunias planted, I’d suggest including them when you spray as budworms really enjoy a good petunia for dinner, too.
Q: Is it best to water my roses and small shrubs overhead or just at ground level? — C.W., West Side
A: Hmmm. Well, all plants enjoy a good spritzing off every now and then but for maintenance watering keep the water at ground level. That way you can monitor the applications and be sure everyone is receiving what they need. Overhead watering is fairly wasteful, too. More evaporates than is utilized by the plants. Also, if the leaves are wet still during the heat of the day, the sun’s rays can magnify through the droplets and burn the surface beneath. Scorched sunburnt leaves do not a healthy plant make.
Now that’s not to say your plants wouldn’t appreciate an occasional spraying off. Perhaps weekly get out there and give everything a quick spray. You’ll remove dust and perhaps small insect infestations before they take hold keeping the plant life healthier. But for maintenance watering do that at ground level and best do it early in the morning or at dusk so the water is more likely absorbed than will evaporate.
Need tips on growing your garden? Tracey Fitzgibbon is a certified nurseryman. Send your garden-related questions to Digging In, Rio West, P.O. Drawer J, Albuquerque, NM 87103.