After my peonies and roses bloom, should I cut off the spent blooms?
In both cases, after flowers fade they proceed to the next step in reproduction: seeds. Peony seed pods are not very attractive or useful, so cut off the old flowers and stems to prevent the peony from wasting energy on them. Spent roses, too, are usually removed before they produce rose hips, which contain their seeds. A generous pruning, however, of the flower, stem and some leaves will stimulate growth and often a second flush of flowers. It's a good idea to let your last roses develop into rose hips for birds to eat in the winter.
There are squiggly light-colored lines on the leaves of my columbine flowers. Some leaves are turning brown. What causes this and how can I stop it?
These are the tunnels, or mines, of the columbine leafminer that is feeding between the upper and lower leaf surfaces. If you pull apart the leaf, you'll see a tiny white larva, technically a maggot because the adult is a small fly. You want to break its life cycle and stop the maggots from pupating into flies that then lay eggs and result in more maggots next year. Pull off and destroy any leaves with tunnels. If the plant is infested with mines, you may need to prune back to clean growth and let it releaf. In the fall, practice good garden sanitation by removing all fallen leaves and plant debris that may harbor this pest.
Is there a way to test mulch? We have always purchased pine fine mulch, but this year's delivery looks like regular hardwood mulch.
Mulch is not a regulated product, so it is "buyer beware" when purchasing mulch. The best practice is to visit the site where you intend to buy the mulch and examine the products they have to offer. Again, when the mulch is delivered, examine it before it is dumped from the truck. If it is not what you ordered or not what you expected, you do not have to accept delivery. Once they have dumped it, however, it is yours.
University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to the website at hgic.umd.edu.
Plant of the week
Kniphofia, Red-Hot Poker
At 3 to 5 feet tall, kniphofia makes a stunning late spring and summer blooming perennial. Pronounced "Nee-FOFE-ee-uh," this plant is also known as red-hot poker or torch lily. Multiple bright flower stalks rise on the tip of a bare stem high above the 1½- to 2-foot clumps of strappy evergreen foliage. The densely flowered torch-like spikes of tubular 1- to 2-inch blooms are particularly interesting, first blooming from the bottom with the lowest blossoms in lemon yellow, while the top ones are orangy-red. The resulting spectrum of hot shades does resemble glowing hot metal. Kniphofias are easy to grow in full sun with well-drained soil. Once established, it is best to leave them in place, however, you can propagate by digging up a crown or two from the edge in the fall.