SALISBURY — July is generally the month of extreme heat and humidity. We’ve had the humidity, and the heat is sure to follow. Below are questions posed by home gardeners earlier this week that may relate to your gardening situation.

Question: I was on my friend’s pontoon boat on High Rock Lake this week and noticed green algae floating on the coves and often in the middle of the lake. What is this stuff?
Answer: These aquatic weeds are most likely duckweed and watermill. Both are very common in ponds, but not that common in an active lake. The weed will die in cold weather. It is often carried to the water by ducks, geese, other waterfowl and animals.

Question: I listened to your radio program last week and you mentioned there were some crape myrtles that only got about 3 feet tall. Can you tell me more about these plants? I didn’t know there were dwarf crape myrtles.
Answer: Yes, there are a number of both semi-dwarf and dwarf crape myrtle cultivars that have a place in most landscapes without constant pruning. Crape myrtles are almost indestructible landscape plants that can adapt and thrive in severe landscape conditions. These plants also adapt well to containers and pocket gardens. There are three new dwarf cultivars in the Southern Living Pocket Garden located at the Agricultural Center on Old Concord Road. These dwarf plants are part of a test for new landscape plant cultivars donated by Southern Living Nurseries plant collection. They are now in full bloom.

Question: My string beans looked good before the rains and all of a sudden most of them have died. When I pulled them up the stems seem to be rotting. What is it and what can I do about this problem?
Answer: Damping off is the problem. It is a complex of many fungal diseases on seedlings especially during rainy, humid weather. Be sure to plant your seed in soil that has been well prepared. The soil should have a pH around 6.5, and use high-quality seed, treated with a protectant fungicide. Thin out crowded plants to allow better air circulation. There are no resistant varieties, though some may be more tolerant than others. Later plantings may not have the same problem.

Question: How do I get rid of poison oak in my yard?
Answer: Poison oak or ivy can be controlled with directed sprays of glyphosate (Roundup) 2 percent solution. It is easiest to kill just before or just after bloom. Broad leaf weed or brush killers will also control the plant and will not kill grass. Always read and understand the label before applying any pesticide.
Darrell Blackwelder is the county Extension director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970, Facebook or online at www.rowanextension.com