Greetings, Grumpians. Today might be my final day in tropical paradise, but that doesn’t mean I can’t take time out from rum, sun, and a warm, sticky bun to answer some gardening questions and introduce you to one of my favorite summer perennials.
Question: My Knockout roses have been beautiful until now. The main plant looks normal, but all new growth is coming out distorted with smaller leaves and rose buds and flowers. What is wrong and how do I correct the problem. Thanks, Karel
Grumpy replies: I suspect your plants have aphids. These sucking insects can be green, brown, yellow, or red and usually gather on the new leaves and flower buds. You can kill them by mixing 4-5 drops of liquid detergent into a quart spray bottle filled with water and spraying both the upper and lower leaf surfaces.
Question: We have a great Natchez crepe myrtle that I let go to seed (didn’t cut off the old blooms) and I need to know if the seedlings will always be the white Natchez? My wife wants to plant them in the front yard, but they “have to be white,” so do you know? Thanks, Arthur
Grumpy replies: Seedlings can be any color. There is no way to tell what color they will be until they bloom. Having said that, Natchez seedlings are more likely to be white than some other color.
Question: I am wondering about planting oakleaf hydrangea and hostas in an area that gets partial shade, but is heavy in roots from a water oak and Bradford pear. I need something I can plant in a row. The trees take most of the water so I know whatever I put there I will need to water in this hot summer heat. The soil is dark loamy with a lot of oak leaf mix on top. Sallie
Grumpy replies: I think the oakleaf hydrangeas (Hydrangea quercifolia) would do just fine there. If you’re planting in a row, make sure you get all the same kind. My favorite is ‘Snowflake.’ Hostas, however, do not like root competition and probably wouldn’t do there. The best perennial I’ve found for dry shade is called bishop’s hat or Epimedium. It spreads slowly to form a patch, stays low, has pretty flowers (whose shape remind some people who know what bishops’ hats look like of bishop’s hats) and handsome foliage, and takes no care whatsoever. Here’s a photo of red bishop’s hat (Epimedium x rubrum). It features red flowers and reddish foliage in spring. You can order bishop’s hat from Digging Dog Nursery.
Question: I live in zone 9 in northeast FL. I have Endless Summer hydrangeas planted at the back of the house. They receive morning sun and afternoon shade and bloom prolifically. However, I am now finding the leaves are getting black spots which eventually cause the leaves to fall off or I have to cut them off. Any ideas? James
Grumpy replies: It sounds like your plants are being attacked by a fungus called anthracnose. Hot, wet weather favors its development. To control it, keep removing diseased foliage. Do not wet the foliage when you water. Spray all healthy foliage according to label directions with a fungicide called Daconil. You can get this at garden centers.