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Compost Bin

I’d like to start composting. Do you have any advice on what kind of bin to purchase/build so that it is successful in the Chicago climate?

Compost, decayed organic matter, improves soil structure, porosity and density and creates a better root system. It increases moisture retention and nutrients while adding significant quantities of organic matter to the soil. It is such a valuable addition to garden soil that it is worth the effort to collect and store waste vegetative material until it decomposes.

Compost bins range from low to high tech. A compost heap can be as simple as a pile of leaves stored at the rear of your garden. The most costly composter is a revolving two-tumbler device with a rotator drum that separates new material from finished material and discharges the final product.

Ideally, if you are saving a mix of unshredded plant material that includes flower stems, large leaves and small branches, a three-bin system works best. Stake out three 36-inch square cages using fence rails, lattice or steel wire. Raw material goes into the first bin. When it is partially decomposed, aerate it and shift it to the second bin, and put the most highly decomposed matter into the final bin. With that method, you can keep adding fresh material as the season progresses.

Do not put any diseased plants in the pile. Keep it in a concave shape to hold rainwater, and aerate it occasionally. As the pile “cooks,” it will heat up during the summer. An interior temperature of 180 degrees will kill bacteria but is not often attainable; 120 degrees is more likely for a mix of green and dried leaves.


Begonias

I start ‘Dragon Wing’ begonia from seed under grow lights. What other begonias can I use to cross-pollinate with the ‘Dragon Wing’ so I can collect my own seeds?

‘Dragon Wing’ is a unique hybrid type of begonia named to reflect the shape of its leaves. It is created by interspecific crosses of two different begonia species and can lead to interesting new plants, but they are sterile.

It is impossible to say exactly which species will cross and which will not cross. You can try crossing angel wing begonia, a common houseplant, with another species. There is a good chance viable seed will be produced, according to Brian E. Corr, new crops development manager at Ball Horticultural Company, West Chicago.

The American Begonia Society (begonias.org) is a resource for information on hybridizing. The archives of the bi-monthly journal The Begonian would also be helpful.


Colorful Shrubs

I am interested in improving fall color in my yard. What shrubs turns red beside burning bush (Euonymus alatus)?

Wendy Vichitk, plant manager at Luurs Garden and Flower Shop, Hillside, recommends these shrubs for a colorful fall garden:

Low growing 2- to 3-foot Virginia sweetspire ‘Little Henry’ (Itea virginica) has red foliage and grows in both sun and shade. The foliage of the somewhat taller ‘Henry’s Garnet’ is dark red, as the name indicates.

Fothergilla ‘Mount Airy’ has blue-green leaves that turn intense yellow and orange-red in sun and half shade.

Oak leaf hydrangea (Hydrangea quercifolia) grows in shade or partial sun, with orange-red to red fall color.
The leaves of apple serviceberry (Amelanchier grandiflora) burn a bright orange red. There are several cultivars on the market to choose from.

Many viburnums have bright fall color. The easy to grow Korean spice viburnum (Viburnum carlesii) and the also fragrant V. juddii have leaves that produce a mixture of red, orange and mahogany. Arrowood viburnum (V. dentatum) and cranberry bush viburnum (V. trilobum) both exhibit typical red-purple color.

The intensity of color is affected by the weather. Warm sunny days followed by cool nights bring the highest leaf color. The health of the plant, its growing conditions, and the amount of water the plant receives also affect fall color.


Nitrogen Problem

I applied commercial compost and hardwood mulch to an area where I am establishing a small garden. I did a few soil tests on the area and the results indicated the nitrogen was depleted. I intend to spread a bag of dried blood to rectify this problem When is the best time to apply the dried blood?

Landscape professionals are usually skeptical about results from home soil tests. They don’t always produce accurate results unless you take a large soil sample from many parts of your yard.

“Take your home soil test results with a grain of salt,” advises Tony Fulmer, manager, Chalet Nursery, Wilmette. He cautions not to become overly excited by the results. “Hard-wood mulch is used by landscapers all over the area, and I don’t see a problem with it causing nitrogen depletion.”

Apply the dried blood now. The 12% insoluble nitrogen starts working when soil temperatures rise.


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.


I've got green worms!

What is the green worm that eats my roses and columbine every year?

It is hard to diagnose your problem without seeing the caterpillar. There are several green worms that bother roses, and one can be controlled with Bt (Bacillus thuringiensis) but rose slug, for example, cannot. Proper identification is necessary before applying any control method. Do not use an insecticide for anything that"s not on on the product label. Do not use any insecticide as a preventive measure. It doesn"t work and ends up being harmful to the environment and a waste of your money.

Green worm on your columbine could be an inch worm or canker worm. If the caterpillar loops up in the center or arches as it moves along, it could be a looper or cabbage worm. Leaf miners, which are usually white or pink, tunnel in the leaves. “To eliminate insects, use insecticidal soap,” said Nancy Clifton, Chicago Botanic Garden Plant Information Specialist.

For an exact diagnosis, consult your local University of Illinois Extension service or collect a specimen and bring it to the Plant Information Service at the Chicago Botanic Garden or the Morton Arboretum.


Purple Coneflower

I have read that purple coneflowers (Echinacea) are a good source of food for birds in the winter. Will they be okay if not trimmed back until spring? If so, how early should they be trimmed?

If your coneflowers remain standing over winter, the seed heads will be available as bird food and will also be an attractive presence in the winter garden. They should be cut back in early spring before April. If you prefer, you can cut the plant back after frost and throw the seed heads on the ground.


Coneflowers

I thought that purple coneflowers were insect proof, but now I see some aphids at the bud and tiny flies. What is wrong?

Purple coneflower (Echinacea purpurea) is a common native perennial that grows best in sandy or well-draining soil and full sun. If you are not giving your plant these growing conditions, certain insects can attack your plants.

Aphids are sometimes visible on buds, and as sucking insects they cause stunted and deformed leaves. Spider mites are tiny insects that often multiply in hot, dry conditions. Spider mites feed on sap and cause yellowish leaves. Thrips are barely visible, tiny insects causing bud malformation.


Overwintering Marginal Plants

I keep seeing photos of interesting plants I’d like to grow, but they’re labeled zone 6 and I’m in zone 5. What can I do to successfully overwinter these marginal plants? I’d like to try them, but I don’t want to waste my money.

“Pushing a plant past the limits of its hardiness is not for the average gardener,” says Marie Dvorak of The Planter’s Palette in Winfield, “but plants can sometimes be successfully overwintered by siting them in a special microclimate such as a sheltered southern exposure.” Another tip comes from horticulturist Ann Hancock at Michigan State University, where they are trialing perennials that the English firm Blooms of Bressingham is introducing in the U.S. Hancock explains that the best way to keep perennials that are tender in Zone 5 or that are rated for Zone 6 is to grow them in raised beds with good drainage because poorly drained wet soils will cause the roots to rot. In addition, it is important to check perennial beds for plants that have heaved out of the soil through repeated freezing and thawing. Replace them in the soil and protect with mulch.

One example of a marginally hardy plant that will be getting attention this year is ‘Flamenco’, a new cultivar of Tritoma (Kniphofia, red-hot poker) that has just been named an All-America Selections Winner for 1999. Tritomas should have their foliage tied upright so water does not remain in the crown, said Hancock.


White Pine Trees

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.

White pines in this area are very rarely troubled by disease. They are, unfortunately, highly susceptible to high pH problems, or soil alkalinity, and are utterly intolerant of salt, according to Rich Eyre of Foxwillow Pines, Woodstock. The browning needles could also indicate the plant is getting too much water or has poor drainage.If environmental problems are not the issue for your white pines, consult an expert. Betty Lockwood, Plant Information Specialist at the Chicago Botanic Garden, suggested you bring them a sample branch to check on disease and bring in an arborist for an on site visit to check your growing conditions. Or take a 12-inch sample of an affected tree to your local extension office.Austrian pine is very tolerant of environmental conditions but is prone to certain diseases—diplodia tip blight and dothistroma needle blight, both caused by a fungus. Only an arborist or a laboratory can provide an accurate diagnosis. If you bring in a 12-inch sample for diagnosis, be sure to sterilize your pruning shears with denatured alcohol after cutting the diseased wood.


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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.

I brought my mandevilla plant into the house to overwinter. How best can I keep it? Will it flower? Can I root pieces of it?

We are first-time gardeners and have planted Brussels sprouts and green and red cabbage that we are trying to grow organically. There are black egg sacs and small green worms eating the leaves. Is there an organic product we can use on the cabbage?

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