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How can I get rid of voles? I think they are doing a lot of damage to my bulbs.

Voles are mice-like rodents that gnaw on roots and bulbs. They are hard to control.

There are repellents on the market that you can try—Deer Off, Moletox, and a new product named Shot Gun Repel. The latter repellent was designed specifically to protect bulbs from chipmunks, moles, voles and mice. Treat the bulbs before storing or planting. Remove old skin and soil, and then spray thoroughly until wet. Allow the bulbs to dry before storing or planting.

Fresh Figs

I recently moved to Chicago from Houston and I miss fresh picked figs. Is there any way to grow figs in Chicago short of installing a greenhouse? Will sunny windows do? I’m desperate.

Figs (Ficus carica) are handsome plants with smooth gray bark and large lobed leaves which can grow into gnarled trees in warm climates. In Illinois, with winter die-back, they are grown as shrubs. They should be sited where they get some protection from the wind in winter.

You do not need a greenhouse to grow figs, and a sunny window would not be appropriate. Grow a fig cultivar suitable for this climate. While most figs are rated to winter hardiness zone 4, the problem comes because our growing season is too short to ripen fruit, which may take until September or October in a cool summer. Sometimes we have an early frost. If so, pick unripened figs and let them ripen in the house.

Alana Mezo, senior horticulturist for the fruit and vegetable island at the Chicago Botanic Garden, recommends ‘Chicago Hardy’ fig, the variety they grow. They have 10 or 12 plants there growing in a row and, through trial and error, have decided not to protect them over winter because rodents chew roots and stems in wrapped plants and set back their growth. Their figs are multi-stemmed, die back to the ground when unprotected, and get off to a slow start in the spring, delaying fruiting.

However, if you do not have a rodent problem, tie the stems together, wrap burlap around the tied stems, and cover the base with a basketful of leaves. With this protection, your plants will have a head start in spring, and you should have figs ripen a month earlier than unprotected plants, at least by late August.

Another method of winter protection is to root prune in a half semi-circle around the plant, lay it down and cover the plants with leaves over winter.

If you grow a fig in a large container, you can wheel it into an unheated garage and store it over winter. Watch it to see if it needs moisture. Your plant does need a dormant cold period, but not a freeze. This is an “iffy” process according to Mezo.

A fig grower in Highwood claims that rubbing olive oil on the fig hastens ripening, but Mezo has not tried this yet.

Siberian Iris

My Siberian iris ‘Gracilis’ plants have only one bloom per clump. I have five 3 to 5 year-old clumps that are 8 to 10 inches wide. They do not appear to be crowded. All are planted in a moist area. Why is there only one bloom per clump?

“Iris bloom is directly proportional to the amount of sun received,” proclaimed Chuck Simon, Hinsdale, past president of the Northern Illinois Iris Society, who grows 10,000 rhizomes of 1,000 to 1,500 iris varieties. Iris need 4 to 5 hours of sun, but full sun is best. Another cause of bloom failure could be iris borers, which eat mature fans and cause only minor increases in plant growth. Spray with Cygon 2E in spring when eggs of borers hatch in order to break their life cycle. When transplanting iris, make sure the roots remain moist. Grow them in moist but not wet soil. In the first year after planting, water them religiously. Once past that point, they are very hardy. Simon, a master iris judge, referred to the American Iris Society checklist for any special cultural conditions affecting bloom and discovered that this variety is very old. Iris siberica ‘Gracilis’ was introduced in 1927.


We moved into a house with a lovely azalea that didn’t bloom. We thought it might have been over-pruned. Last fall we did not prune it and now it still hasn’t bloomed. I was hoping to transplant it this year, but it looks rather sickly. Shall we prune it again and give it another year? Can I still transplant it?

Stop pruning your plant since you may have over-pruned it. Evergreen azaleas only need tip pruning in July after their flowers have faded.

Concentrate now on rebuilding the azalea into a healthy plant. Do not transplant a sickly one. Feed your plant regularly with an liquid acidic fertilizer. Keep your plant weeded and its roots moist by using mulch because azaleas are surface rooters. Make sure your plant is situated in soil with good drainage and in a part sun/part shade location.

Try this regime over summer and evaluate your plant next spring, advises Charlene Wooten, manager, Cedar Hill Nursery, Lake Zurich.

Fruit Trees

I am interested in growing fruit trees in my suburban DuPage County yard. Can sweet cherries be grown here? Can you suggest varieties of apples, pears, peaches, apricots and plums that are hardy and disease resistant?

Sweet cherries are not hardy in this area. Some fruit trees are sensitive to winter cold and spring frost damage to the buds. Early flowering apricots are the most sensitive, followed by peaches. Pears and sour cherries bloom later and are less sensitive to late frosts.

Apples are the least sensitive to frost damage. Apple scab and apple maggot are common pests. Fruit trees require a regular schedule of spraying for pest control.

For a backyard fruit tree grower, tree size is important. Dwarf fruit trees bear full-sized fruit earlier than standard sized trees. Most fruit cultivars need two different varieties to cross- pollinate and produce fruit.

Midwest Fruit Explorers is a non-profit amateur backyard fruit-growing group. For more information about fruit growing, see www.midfex.org.


What ratio and amounts of fertilizer would you use for a perennial bed and a vegetable garden? For growing annuals in a greenhouse, should the fertilizer be fast or slow-release, organic or inorganic?

Use 3 to 5 pounds of a 10-5-10 or 10-10-10 fertilizer per 1000 square feet in the perennial bed. Add leaves as mulch. In your vegetable bed, nutrients are important. Fertilize more heavily using a 10-10-10 fertilizer at the rate of 5 to 10 pounds per 1000 square feet.

For hanging baskets of annuals in a greenhouse, a slow-release fertilizer is best. Use a 20-10-20 liquid fertilizer following label directions. In general, organic fertilizers have a lower chemical analysis than inorganic ones, so you have to use more, according to David Tyznik, owner of Planter’s Palette, Winfield.

A healthy plant is dependent on its soil. A balanced soil is rich in beneficial microorganisms that improve the soil structure and supply necessary nutrients. Soilless potting mixes have no microorganisms. “Both organic and inorganic fertilizers work well, but those in soilless mixes need more fertilizer,” says Tyznik.

Planting Tulips

Is there a best time to plant tulips? I see them at the garden centers in late summer but I am afraid that it is too early to plant them. If I wait too long, I might forget all about them.

Fall bulb planting should wait until soil temperatures drop to 55 degrees or cooler. This usually occurs when nighttime temperatures drop to 50 degrees or lower for two weeks or more. While waiting to plant, store the tulips in a cool, dark place away from direct sunlight—but don’t forget them. After planting, water the bulbs well, advises the Netherlands Flower Bulb Information Center.

If you plant grape hyacinth bulbs amidst your tulips, they will come up early in the fall and serve to mark the position of your tulips.

Cold Frames

With all the emphasis on growing fresh vegetables, I think I should use a cold frame but I am not sure what to do or how to go about it. Any ideas?

Cold frames are simply four walls with a window or plastic sheet on top. They range from simply placing four bales of straw in a square with an old window atop them to more deluxe mini-greenhouses with aluminum frames, plastic panels and automatic vents using solar energy to open and close them automatically.

Before building a cold frame, study garden supply and greenhouse catalogs to determine your needs and how fancy you want your cold frame to be. Do you prefer a permanent installation or an easily disassembled frame?

A basic plan for building a cold frame is taught by Chicago Botanic Garden’s senior horticulturist Heather Sherwood. Create four walls from plywood or bricks. Add a transparent lid (plastic sheeting or an old window) for light to enter. Place the lid on an angle. Place the frame against a building, facing south. Make sure there is good drainage. Open the frame when it gets above 60 degrees. Rabbits don’t usually get into the box but chipmunks may squeeze in.

Cold frames are used for extending the growing season, starting plants early, for storing bonsai or protecting semi-hardy plants over winter. The soil in the frame depends on how you will use it. The frame can be set on existing soil when you are storing plants, or fill it with straw to protect bonsai. Locate it conveniently against the house near a back door for easy access, especially if you envision running out to cut some salad greens when snow is on the ground.

Use a cold frame to get a head start on the gardening season. In early spring, start flats of lettuce, radishes, parsley, pansies and other cool-weather plants in the house, and place them in the cold frame in March, depending on the weather. If you plan on planting directly into the cold frame, fill it with a seed starting soil mix and an inch of compost worked into the top 3 inches of the soil. This will help keep the soil loose and aid moisture retention. The plants will be small in the cold frame and can be grown close together. Also use the cold frame to harden off house-grown seedlings.
Don’t forget to check on your plants regularly because winter sun is strong and plants dry up easily. Use it for a head start on the gardening season.

Large Tree Replacement

What is the largest tree that one can plant? We are trying to replace some 7- to 8-foot trees that were recently destroyed.

Trees sold at garden centers that are 2.5 to 3 feet tall, with a 2.5 inch diameter trunk, can be planted by hand. A hole for a ‘balled and burlap’ tree with a 5 to 6-inch diameter trunk can be dug by hand without a tree spade.

Any tree with a trunk larger than 6 inches in diameter would need a tree spade to do the moving and digging. Even large trees, such as a 35-foot tall tree with a trunk 9 or 10 inches in diameter can be transplanted with proper equipment. “Spruces 30 feet tall can be installed easily with a tree spade,” according to Greg Oltman, owner, Gro Horticultural Enterprises, Huntley.


Late last year most of the leaves on my year-old seven-son tree (Heptacodium) turned brown, starting at the tips. It had some new growth on the tips and buds. I used a tree ring soaker hose every two weeks.

“I suspect that your watering every two weeks was not sufficient and that your tree was going into early dormancy,” says Chicagoland Gardening editor Carolyn Ulrich. “It was very dry late in the growing season and a lot of trees looked stressed.”

A rule of thumb for watering is one inch per week. Heptacodiums grow best in moist soil. You probably needed to increase the amount of time the water was on the plant and also water more frequently. Soaker hoses can run for hours.

If you want to figure out how much water your tree is receiving, use a sprinkler, if you have one, and run it on your tree until a tuna fish can has an inch of water in it, and then stop. Do this weekly, unless it rains.

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I plan on saving my amaryllis bulbs that I kept outside over summer, but I noticed red streaks on the inner side of the leaves. What caused that? Will I be able to save my bulbs?

I have lost four 12-15 foot tall white pine trees over the last year. All had the same symptoms, browning needles at the bottom that continued up to the top. Can you tell me what pest is killing the white pines? I am also losing an Austrian pine now. It is experiencing the same symptoms.