The Plant Lady: Answers to your most-pressing garden questions. Are your roses OK?
Gardeners face common problems. We’ve all dealt with water issues or pests at one point or another. This week we answer some common questions about tomatoes, zucchini and roses in an effort to get everybody’s plants blooming the right way.
My zucchini gets to about 2 inches long and then rots — why?
This will happen when the flower is not fully pollinated. Each flower needs to be visited by approximately 5-10 pollinators (typically bees). A fruit is actually a mature ovary. On squash and other cucurbits, the immature fruit (ovaries) are often noticeable under the base of a flower. When a flower is not pollinated or partially pollinated, it will either abort or grow slightly and then abort.
Early in the season it is more common for this to happen, as there are not as many flowers present. If poor fruit set persists, take a small paint brush and hand pollinate. Locate the male flower, which is the one lacking an ovary. Simply wipe the paint brush over the stamens (male reproductive parts) and coat the brush with pollen. Next, find a female flower (look for the ovary) and wipe the paintbrush across all the stigmas (female parts). This should be done in the morning, as the flowers will close midday. It is okay to cross-pollinate different plants with pollen. A good practice is to remove the petals of the pollinated flowers so the petals do not stick to the stigmas as they die. For visual demonstration of hand pollination, check out my YouTube video at Marlenetheplantlady.
Why do my roses have half-circles chewed out of the leaves?
Leaf cutter bees have very distinct chew marks. They create smooth, half-moon circles out of the sides of leaves. Do not worry as these bees are not problematic and the damage is almost always benign. The female bees use the leaf material to build nests for their young. Not only is their damage minimal, but they are also good pollinators for the garden.
What can I do for blossom end rot on my tomatoes?
Blossom end rot is caused by the lack of calcium making its way into the fruit. It is very distinguishable as it manifests as a brown/black area at the base of the tomato (the part where the bloom was attached). Calcium is crucial in the building of cells, and when it is lacking the cellular structure is not fully formed. However, rarely is it an actual lack of calcium in the soil. It is almost always do to the plant not being able to utilize the calcium based on environmental problems such as soil moisture/temperature.
The first set of fruit is the most affected because this is set when temperature/moisture is still uneven. The most effective control is to regulate soil moisture. This can be done by applying mulch and watering evenly to prevent periods of dry and overly water saturated soil.
Blossom end rot calcium sprays are not effective. Calcium — when absorbed by leaves — is not transported toward fruit. When sprayed directly on fruit, the skin is very poor at uptake of any mineral. It can often be deceptive, as it may seem that these sprays work because by the time the second round of fruit is formed, the soil temperatures/moisture has evened out for the season.
I planted a Hydrangea recently and now the flowers have dried up and the leaves are browning and shriveling. What do I do?
When planting during warm months it is not unusual for plants to go through a bit of a stress period. Normally, to eliminate stress they will drop leaves to prevent water loss (thus halting photosynthesis). The good news is most of the time the root ball is still alive, and it is only a matter of time before it will establish and regrow. During this period do not overwater, but keep the soil evenly moist. Remove the spent flowers, but do leave the canes. Mophead hydrangeas flower on previous year’s growth, so if you were to cut them down they will most likely not bloom the following year.
My Angel’s Trumpet has holes being eaten out of the leaves. What is causing this?
Most likely it is the larvae of the cabbage looper or cabbage white butterfly. They will lay their eggs on the underside of the plants and the larvae will munch away at the leaves. You may also notice their black granular excrement. Hand picking off the pests is one solution, however they tend to blend in with the leaves so you will have to look closely. BT (Bacillus thuringiensis) is another option. This naturally occurring soil bacteria is either sprayed or dusted on the leaves. The larvae will ingest it when they snack on the leaves. They are unable to digest the BT and die. It is safe to use around people and pets. Do note BT does break down in the sun, so reapply every few days. Also remember your plant can handle a decent amount of damage if it is healthy and robust, so it is not a death sentence if you have an infestation.