Good bedfellows

Q I'd like to grow some vegetables this year, but the only sunny space I have is in my flower garden. Can I mix flowers and veggies or do I have to keep them separate?

A You're one of a growing number of gardeners who want to raise food as well as flowers. Because vegetables need a lot of sunlight -- preferably all day -- the idea of combining your flowers and vegetables makes a lot of sense. But there are a couple of things to keep in mind if you're going to mix the two.

• When planning and planting in the spring, be sure to take into account how big your vegetables will be when they mature. Allowing for a little air circulation around plants helps avoid diseases. Consider height as well as width: You don't want taller plants to shade shorter ones. Vegetables that get shaded as the season progresses are slower to bloom and, ultimately, less productive.

• Some vegetables (including tomatoes, peppers and squash) stay in the garden throughout the growing season. Others (including snap beans, carrots and leaf lettuce) can be removed as soon as you're done harvesting them. It's a wise idea to plan for filling empty spaces left in the garden after you remove spent vegetables. At the very least, you'll want to fill the space with mulch to prevent weeds from moving in.

• Think twice before using pesticides in your combo garden. Insecticides you might have used to battle aphids and fungicides that you used to combat powdery mildew may not be OK to use on edible plants. Read the labels carefully.

Preventing aster yellows Q Last summer, some of my coneflowers got aster yellows. Many of the flowers were distorted and greenish, so I dug them out. But I really like coneflowers and I'd like to plant them again in the spring. Can I plant new ones in the same place where I removed the diseased plants?

A You can try, but there's no guarantee that the new plants won't become infected. That's because aster yellows is introduced and spread by leafhoppers. These insects spread the disease-causing phytoplasma (bacteria-like organisms) from plant to plant as they feed.

Trying to control leafhoppers isn't recommended because it would require spraying frequently throughout the entire growing season. And even then you can't be absolutely certain to avoid aster yellows.

Drought-tolerant grass Q What type of grass should I plant in parts of the lawn that depend mostly on rainfall for moisture? Are there any good heat- and drought-tolerant lawn grasses?

A Unfortunately, the lawn grasses that stand up best to hot, dry conditions are not well-suited to growth in northern climates. Even though they may be winter-hardy here and do well in July and August, they don't produce a nice-looking lawn from spring through fall.

Two grasses that are sometimes suggested for hot, dry conditions are zoysia and buffalo grass. But neither turns green until late spring, when our weather is consistently warm, and both go dormant as soon as nighttime temperatures grow chilly in fall. Although buffalo grass is native to the Dakotas, it grows in clumps or bunches and doesn't produce the carpet of green most of us aim for. Zoysia is slow to spread and appears as a coarse weed amid finer-bladed bluegrass lawns.

Your best bet might be a combination of common Kentucky bluegrass and creeping red fescue. The fescue is more drought-tolerant, but lies flat unless planted with other grass seeds. Common Kentucky bluegrass has the ability to go dormant in very hot, dry conditions and remain viable with only minimal watering every couple of weeks. It revives and turns green again with the advent of lower temperatures and renewed rain, typical for us in fall.

A The black-eyed Susans (Rudbeckia hirta) are generally treated as annuals or short-lived perennials. Blanket flower (Gaillardia x grandiflora) is also a short-lived perennial.

Seeds of both plants can be started indoors about eight weeks before the last frost date (which is about mid-May in the Twin Cities area).

Sow the seeds in damp, soilless potting mix and provide lights. (Fluorescent bulbs in a shop-light fixture work fine.) The lights should be kept just a few inches above the plants. Raise the lights as the plants grow.

Harden off the young plants in May by moving them outside each day for longer periods, eventually leaving the plants outside for several days before planting them in the garden.