Q. I have tried to grow delphiniums in my perennial border for several years, but have not had much luck. Can you suggest anything that would help me grow better plants?
A. I do not recommend growing delphiniums in Baltimore. Delphiniums are cool-season plants that like moist, rich, fertile soils. They grow well in such places as New England and the Pacific Northwest, but they are very difficult to grow in eastern Maryland. It is simply too hot here in the summer.
In gardening, we often try to manipulate the environment and force things to grow where they do not belong. Sometimes we are successful. For example, perennial astilbes like rich moist soil, and we can grow them if we work organic matter into our soil and give them supplemental water.
However, we have little or no influence on the temperature and cannot make it cool enough for delphiniums. Though it is difficult to find a replacement for delphiniums, I would look for another plant to grow in your garden.
Q. We have several active dogs that run in our fenced yard. They can be very hard on plants. How can we build a nice garden for both dogs and plants?
A. It is very important to define the boundaries that separate the dogs' play area from the garden. You can do this by building raised beds or bordering beds with rocks or small, stout shrubs.
The plants you select must be tougher than the pets, and preferably larger, so they cannot be run over.
Some small, colorful barberries and spireas are large enough and tough enough to be used as border plants with small to medium-sized dogs. Tall annuals or perennials could then be planted behind the shrubs.
If you have a small yard, or if you would like to plant a lot of tender annuals, perennials or vegetables, I would build raised beds. This may be the only way to have both the dogs and the plants you love.
Checklist
1. The foliage of daffodils and tulips has died back to the ground. It can be cut and removed to the compost bin, or it can be left as mulch for the soil.
2. When plants look unhealthy, be sure to look at the whole plant for clues to the causes. The undersides of leaves harbor many pests.
3. Second crops of bush beans can be planted now and will be ready for picking in mid-summer.
Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site, www.hgic.umd.edu.