Q: My neighbor has planted morning glory vine against a block wall that we share. The vines have grown up into her juniper trees. Last year I planted a vegetable garden on the other side of the wall, but I did not get much productivity from my garden. I think the roots from the morning glory are keeping my vegetable plants from producing. What can I do?
A: Morning glory (Ipomoea purpurea) is considered an agricultural weed. Although its flowers are quite beautiful, it can quickly become a problem. The vines become entangled in anything within reach, and the plants can become enormous. They enthusiastically re-seed themselves, so each year the mass of vines grows bigger.
You mention that the vines have grown into your neighbor’s juniper trees. I suspect that both the trees and the vines are shading your vegetable beds, which would explain why you are getting such poor yields.
You might try to convince your neighbor to remove the offending vines, but you may have to relocate your vegetable garden to a less shaded location.
Q: I have quite a few houseplants, but lately I’ve been seeing little gnats flying around some of my plants. What are they, and what can I do to get rid of them?
A: Fungus gnats (Bradysia coprophila, Bradysia impatiens) are tiny flies that lay their eggs in soil. Within a few days, larvae hatch and begin feeding on algae in the soil and/or root hairs of your plants. If an infestation is severe, the larvae may feed on the root interior, causing plant collapse. Propagation and seed trays seem to be particularly susceptible to infestation.
Biological control is the safest course. Bacillus thuringiensis israelensis (Gnatrol) is related to the organism in commercially available caterpillar killer, but it is targeted to fungus gnat larvae. You should be able to find it at your local garden center or online.
Q: My cacti are covered in a bright red substance, and it seems to be causing the plants to decline. What is it, and what can I do to save my cacti?
A: Cochineal scales (Dactylopiidae) infect several types of cacti, including Opuntia, Platyopuntia, and Nopalea. They measure between 1/16 to 1/4-inch long, have a bright red body, and are often coated in a sticky wax. Severe infestation can lead to stunted growth and chlorosis (yellowing). Treatment includes removal of affected limbs/pads, blasting with a strong water jet, and application of insecticidal soap.
Interestingly, cochineal has been considered a valuable resource. In the Canary Islands, Mexico, and Peru, the insect has been farmed (and smushed) for red dye. For a number of years, it was replaced by carmine, but has recently come back into favor as a less toxic alternative.
Have gardening questions? Email email@example.com.
Looking for more gardening tips? Here’s how to contact the Master Gardener program in your area.
Los Angeles County
firstname.lastname@example.org; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/
email@example.com; 949-809-9760; http://mgorange.ucanr.edu/
firstname.lastname@example.org; 951-683-6491 ext. 231; https://ucanr.edu/sites/RiversideMG/
San Bernardino County
mgsanbern@ucanredu; 909-387-2182; http://mgsb.ucanr.edu/