The second week of January is a good time to spray fruit trees and roses for summer insects and disease. Organic gardeners can get a jump on pests by using a horticultural oil spray that is safe and effective. The oil coats the overwintering insect eggs and disease spores for a fresh start in the spring. The good news about the freezing weather we experienced this winter is that many garden pests were eliminated – but the good as well as the bad insects will be missing this spring. If you decide to use a dormant oil spray in your garden, keep these tips in mind:
1 – Spray only when the temperature is above freezing.
2 – Don’t do the deed on a windy day.
3 – Cover any concrete walkways or patios if you must spray plants close to your hardscaping. Dormant oil sprays can stain hard surfaces.
If you have peach trees, you’ll have peach leaf curl in our rainy climate. Winter is the time to spray lime sulfur or fixed copper on your peach trees to discourage this fungus among us. Garden centers and nurseries will put these dormant oil sprays on sale this month and can offer more advice on how to use them.
Q. I saved my geraniums from last summer by placing them, still in pots, in my basement. The plants still look like they are alive but the lower leaves are turning yellow and dropping off. What should I do to keep my geranium plants alive until spring? P.P., Bellevue
A. First, congratulations on overwintering your geraniums. (All of my geraniums turned to compost after the December freeze.) Don’t worry too much if only the lowest leaves are turning yellow as that is a symptom of too little sunlight. By the end of the month you should bring your potted geraniums closer to a bright window or fluorescent light source so they begin to wake up. Continue to increase the sunlight but only water when the top inch of soil is very dry. In April you can pinch the tops off to make the plants more bushy and begin to fertilize. By this time you’ll want to give them maximum sunlight in a bright window and even move them outdoors on mild days. Don’t let your geraniums stay outside until all danger of frost is past – around mid-May. Be patient, as geraniums that have been overwintered usually take until mid-summer to bloom and look bushy. Or you can put up with just a few overwintered plants and start with some fresh geraniums this spring. This has not been a good winter for saving plants.
Q. Last summer I planted a black-eyed Susan vine that you recommended on HGTV for a orange-themed garden. This vine did great in the summer and covered not only a trellis but grew onto a shed roof as well. My question is, will my black-eyed Susan vine come back next summer? W., e-mail.
A. No, my sympathies but your black-eyed Susan (or Thunbergia alata) is surely deceased. This is an annual vine in our climate. That means you just get to enjoy it once and it needs to be replanted annually. The good news is that this is an easy vine to grow from seed started indoors. You can also find young plants of Thungberia for sale at local nurseries that can be set out into the garden in May. This old-fashioned vine now comes in more color combinations than the bright orange variety with the black centers. ‘African Sunset’ is a cultivars with shades of peach and rose while “Lemon Star” has sunny, yellow blooms.
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Marianne Binetti has a degree in horticulture from Washington State University and is the author of “Easy Answers for Great Gardens” and several other books. For book requests or answers to gardening questions, write to her at: P.O. Box 872, Enumclaw, 98022. Send a self-addressed, stamped envelope for a personal reply.
For more gardening information, she can be reached at her Web site, www.binettigarden.com.
Copyright for this column owned by Marianne Binetti.