Ask the Gardener: Caterpillars, mystery flowers, onions and more

Gardening editor Doug Oster gets asked a lot of questions. A lot. And he doesn’t mind offering gardening advice. But rather than just limiting those answers to the person who asked, we thought it might be a good idea to share that wealth of knowledge with everybody.

There are three ways to send in your questions:

• Email askdoug@535mediallc.com

• Submit your question on our “Your Garden” section of our site

• Send us a message on Facebook.

(The questions may be lightly edited for grammar/clarity/etc.)

Question 1: Caterpillars

caterpillar

Dave: Our daughter is a new (container) gardener who has had a lot of initial success the past two years. Recently, she found these caterpillars eating her kohlrabi, tomatoes, and basil plants. She has been trying to eliminate them by hand picking them off the plants and digging up their eggs in the soil. Seems like a never-ending struggle. She lives in southern Maryland, near the Chesapeake Bay. What can she use/do to eliminate them from her second-floor porch garden?

Doug: The organic controls for caterpillars are first hand picking and then something called Captain Jack’s Dead Bug Brew. It’s not a poison, but effectively deals with the pest after the caterpillar ingests the product. Hope that helps.

Question 2: Mystery flower

mystery flower

Denise: I did not plant this flower, but it recently popped up in my flower garden. Do you know what this flower is? I’m at a loss.

Doug: That’s torenia, a shade-loving annual and good substitute to grow something instead of impatiens. Did you have it in the garden last year? Sometimes they will drop seeds and then sprout. I’d transplant it into a container and get it going for the end of the season.

Question 3: Onions

Pat: How do you keep your onions over the winter? Mine are a nice size. They are drying on the porch. Don’t want them to rot.

Doug: I do it a couple of different ways. Bunching onions are left in the ground and covered with straw. Most years they overwinter and sprout again in the spring. For your nice-sized onions, the drying or curing process should be done in a warm, dry place with low humidity. I’d be tempted to bring them in and continue the curing process on a screen, maybe in the basement. It’s been so humid outside, that will negatively affect the curing process. Which means the onions won’t store as well. Curing is a three-week process, then the onions can be stored either in a mesh bag or laid out flat with good air circulation.

Question 4: Rhododendrons

Joan: The landscaper trimmed a new rhododendron and took all the buds off several years ago, and it hasn’t bloomed since. It is in morning shade and partial afternoon sun. What can I do?

Doug: I would apply an organic granular fertilizer called Hollytone to the plant. You could get away with a light application now and then the full amount in late April. Sprinkle it around the base of the plant and gently scratch it in. Be careful though, the plants are shallow rooted.