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by Rett Davis | |
Gardening Q&A by Rett Davis appears in
Alamance County's daily newspaper, The Times-News,
every Sunday in the Accent section. Each week's installment is
posted to this
website, beginning with January of this year. Scroll to the bottom of
this page to navigate to other Gardening Q&As. Please contact
Rett via e-mail with questions
or
comments in regard to this column.
Question:
I went to work this morning to find the yard covered in hornet-like insects. The employees are nervous about being stung. What should we do?
Answer:
What you have described and after I visited the site confirmed the emergence of an insect called the cicada killer. Cicada killers are in a group of insects we call 'hunting wasps'. They are solitary wasps and do not produce a colony as do yellow jackets, hornets, or paper wasps. Instead the female works alone building a nest to lay her eggs and then provisioning them with food. In this case, the food is a paralyzed cicada. The young grubs of this wasp will feed on this cicada. The behavior you are observing are the males acting all crazy with aerial displays and dogfights to establish dominance and territorial rights. Males of most species tend to act this way to impress the opposite sex. These males have just emerged from the soil where they have spent the last 10 months. In just a matter of days if not hours, they will fly away. They usually nest in the same spot year after year. They seem to like open, sunny, and sparsely vegetated areas. Females will revisit this site soon to dig individual holes to lay her eggs and the cycle starts over again. These wasps will not attack you. The females can sting if you grab them though. There are very few reports of anyone every being stung. My advice is to leave them alone because there are really no practical controls anyway and the 'problem' is very short term.
Question:
The leaves on my tomato plants are turning yellow and have spots on them. What should I do to keep them alive?
Answer:
At this time of the year the leaves on tomatoes will be infected with more than one tomato disease. These diseases will show up on the stems and on the fruit in time. The most common tomato diseases present now are early blight, bacterial leaf spot, and anthracnose. None of which you can do anything about this late in the season. All tomato varieties are susceptible to these diseases. There are fungicides that will slow the development of these diseases but it is too late to apply them. They must be sprayed the week of planting and every week thereafter. Homeowners do not have access to the products that really do the job. So what is left to do? Always plant a second crop 3-4 weeks after your first planting to guarantee tomatoes until frost. Next year move you tomato plants to a new area if you can, mulch them with some material to prevent soil splashing on the leaves, and do not wet the leaves when watering.
Question:
My impatiens plats are starting to rot at the base of the plant and some stem have broken in half. What is wrong?
Answer:
Impatiens will show problems like you have described when we overwater them. When temperatures get into the 90's it is not uncommon to see impatiens wilting during the middle of the day. Shortly thereafter, nervous gardeners will soak the plant with water to alleviate what appears to be a plant in trouble. In actuality, the plant just cannot replace the water it is losing through evapotranspiration fast enough and therefore wilts. But there is still plenty of water in the soil. These impatiens plants will recover during the evening. Saturated soils further the development of stem diseases and the plant is now in trouble and will not recover. So avoid the urge to water impatiens every day. Do not water them until you see that they are wilted in the morning hours. That is a much better indication of their water needs. You may not have to water but once a week if then.
Question:
I am constantly told to add peat moss to my planting holes for everything from trees to flowers. Is this really necessary because it can get expensive?
Answer:
The addition of peat moss to planting holes is a general recommendation that has endured over time despite the evidence and research that we do not need it especially for clay soils. It would be good in sandy soils though. But for a majority of Alamance County residents that are trying to grow plants in soils that are well suited for the production of bricks, adding peat moss can cause a problem. Our clay soils by design hold water. Materials such as peat moss actually hold water too. So adding a substance like this to a soil that by nature is poorly drained often causes more problems. Too much water will lead to the demise of many of our favorite landscape shrubs and flowers. If you want to add a substance to our clays that increase aeration (roots need air too) and that will aid in rapid root establishment, add compost, pine bark fines, pea gravel, or composted manure products. If you are blessed with good topsoil, you need not add a thing.
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