QI bought a couple of varieties of coleus last spring. I really liked them in my patio planters, and I thought I'd start them from seed this year, but I can't find these varieties listed in any of the seed catalogs I get. Do garden centers start the plants they sell, and where do they buy their seeds?
AGarden centers can produce all those flats of annuals and vegetable plants in several ways. Many are started from seed by wholesale growers; some are started by the garden center. Garden centers may buy the seedlings from the wholesaler as plugs (these are small plants with a root ball not much bigger than a bottle cap) which the retailer then plants into a larger cell pack or pot and grows on. Wholesalers also sell many finished plants to garden centers.
There are seed companies who deal strictly with large growers. They carry some of the same varieties that you might find in your seed catalogs at home, but they also carry additional varieties, often in a wider range of flower colors. And, of course, they sell in wholesale quantities.
In the case of your coleus, however, it may not be a seed question at all. Coleus can be started from seed, but many of the coleus varieties sold as plants in garden centers are started from cuttings, not from seed. Check with the garden center where you purchased your coleus last year. They should be able to tell you if they were grown from cuttings. You can always buy more this year, then root some cuttings of the plants in late summer. You can carry these through the winter as houseplants in a sunny window, then start more cuttings to set out in the spring.
QIn the recipe for homemade rabbit repellent in the Feb. 28 issue, you listed an ingredient called spreader sticker. What is this?
ASpreader sticker is an additive that helps sprays stick to leaf surfaces. Sprays applied to leaves that are very smooth or that have a waxy surface tend to bead up and roll off of the leaf, which means the active ingredients in the spray are not able to do their job. Spreader stickers can be used with many insecticides and herbicides, but be sure to read all labels before mixing any products.
There are several brands of spreader stickers available at nurseries and garden centers or wherever pesticides are sold. It is not absolutely necessary to include this ingredient in the rabbit repellant, but it should make the spray stay on the plants longer.
QWe want to plant gardens around our cabin near Hinckley. There are lots of deer around, so I need suggestions for annuals and perennials that deer won't eat.
AGarden and landscape plants provide a smorgasbord for browsing deer. In the summer deer will eat both foliage and soft new stem growth, and in winter they will eat twig tips of woody plants. Deer seem to favor some cultivated plants more than others, but any plant is subject to browsing.
Lists of deer-resistant plants vary in different regions of the country, so a plant that deer rarely eat in Massachusetts may actually be eaten by deer in Minnesota. That said, here are some plants that sources list as deer-resistant:
Anise hyssop (Agastache)
Bleeding Hearts (Dicentra)
Miscanthus (an ornamental grass)
Globe thistle (Echinops)
Lenten rose (Helleborus )
Bee balm (Monarda)
Russian sage (Perovskia atriplicifolia)
Lamb's ear (Stachys byzantina)
Purple coneflower (Echinacea)
Toadflax (Linaria maroccana)
Bells of Ireland
Swan river daisy (Brachycome)
Snow on the Mountain (Euphorbia marginata)
Straw flower (Helichrysum)
Spider flower (Cleome)
Cup flower (Nierembergia)
Floss flower (Ageratum)
Grape hyacinth (Muscari)
Bugle weed (Ajuga reptans)
Dead nettles (Lamium maculatum)
Moss pink (Phlox subulata)
Sweet Woodruff (Galium odoratum)
QCan you tell me why the bottom leaves of our peonies turn brown, as if they have a blight?
APeonies are susceptible to several fungal diseases that can cause spots or blotches on their leaves and stems. Botrytis blight is most prevalent during wet, cool weather, although it can appear at other times as well. This fungus affects new, growing shoots in the spring and can continue to affect mature foliage. You may see large brown patches that are covered with a fuzzy grayish mass -- these are the fungal spores. Phytophthora is another fungal blight that can infect peony leaves and stems. It can cause large dark patches on the leaves and can also kill whole shoots. There are several other fungal diseases that may cause various spots on leaves and stems.
Good sanitation is the first step in preventing these diseases. Make sure the peonies are growing in a site with good soil drainage and good air circulation. Consider moving the plants to a better site if necessary. Cut back and dispose of the foliage in the fall. If you see diseased leaves during the growing season, cut them out and put them in the trash.
Fungicides may prevent some of these fungal organisms. It's important to remember that fungicides work to prevent an infection before it starts, not to cure it once it's there. This means that you need to apply fungicides before a fungal infection starts. Start spraying early in the season and be sure that you cover all of the plant. Read the fungicide label carefully so that you know it's approved for peonies, and follow the instructions carefully for quantities and frequency of sprays.
-- Nancy Rose is a research horticulturist at the Minnesota Landscape Arboretum. To ask her a gardening question, call 612-673-9073 and leave a message. She will answer questions in this column only.