Q. Is there a plant that will repel mosquitoes from the garden?

Q. Is there a plant that will repel mosquitoes from the garden?

A. The plant most often touted for its mosquito-repellent qualities is a scented geranium that is rich in citronella. Citronella is an effective mosquito repellent, but the mere presence of the plant has no impact on the number of mosquitoes that may be found in your yard. You must crush the leaves to release the citronella and rub them on yourself for any benefit.

There are other sources of the same compound in the herb world. Lemon thyme has been shown to be one of the best, because the foliage contains higher amounts of citronella than the scented geranium does.

If you really want to reduce the mosquito population, patrol your home and immediate neighborhood for sources of standing water. Many mosquitoes, particularly the vexing Asian tiger mosquito, breed in surprisingly small and ephemeral pools of water. Check rain gutters on structures, pet bowls, pot saucers and trash receptacles. Often eliminating this standing water has more impact than anything else you can do.

Q. Each spring, I enrich the soil in my tomato beds before planting. The compost I use is high in nitrogen, and as a result my plants grow large and leafy but don't produce a lot of fruit. I heard that you can increase the yield by removing most of the leaves from the plants. Is that an option? How many leaves does a plant need to continue to grow?

A. You don't need to enrich the soil every spring with compost. Frequent watering also may lead to the development of luxurious foliage at the expense of fruits, as will lack of good sunlight for any portion of the day.

Also, your tomato variety plays a large role, determining whether plants grow to a given size and produce their fruit quickly or keep growing as long as conditions of light and temperature allow, setting new fruits as they grow.

All tomatoes benefit from sucker removal. Suckers are new growths that appear in the axil between the leaf and the stem. This is the same point from which flower clusters arise, and often both a flower cluster and a sucker may grow in the same axil. By removing the sucker, you direct the plant's energy into fruit production and also create the sort of open plant that is better equipped to resist foliar diseases.

Pinching out the suckers is a task that must be done frequently as the plants are growing. Removal of large, well-developed suckers may create large wounds along the stem and is of little benefit to fruit development.