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Tree Position

What is the correct distance from my house to plant a tree? What is the correct distance from the lot line to plant a tree?

It depends on the size of the tree you are planting. A small tree such as a serviceberry (Amelanchier) or a dwarf flowering crab could be planted as close as four to five feet from the house. For a birch tree, a distance of six to eight feet would be the minimum.

Distance from the lot line does not matter as long as it doesn’t interfere with power or sewer lines. You should check with your village before planting. Closeness to the neighbor’s lot line is not an issue, because neighbors have the right to trim back any overhanging branches, according to Matt Zerby, partner in Wasco Nursery, St. Charles.


Osteospermum

Can you tell me if the African daisy Osteospermum ‘Springstar Aurora’ can be winterized here? It is a healthy plant?

Those South African daisies could never endure a frigid winter here and should be considered annuals. Their daisy-like flowers with blue centers open only in sunlight and bloom best in early summer or later when summer days cool down. They can be seed-grown under lights.


Sowing Seeds

I would like to start seeds under lights. When is the best time to start flower seeds? The seed packet always says to sow a number of weeks before the last frost. When is the last frost?

“In this area we use May 15 as a benchmark for the last frost date, but it can be earlier or later,” says Chuck Prosek, grower at Prosek’s Greenhouse, Winfield.

If your seed packet gives you the number of days to germination, add that to the number of weeks for growth, and then count the number of weeks back from May 15. Tomatoes sown indoors generally need 6-8 weeks of growth before being set out.

Many seed packets do not include germination time. A good guess is to allow 1-2 weeks for the seeds to germinate, but if you use bottom heat, your seeds will germinate earlier and grow faster. Most seeds need warm soil of 65 to 70 degrees to germinate and grow.

When you sow seeds directly into the soil, till the upper inch of soil to loosen it for direct seed to soil contact. The outside soil temperature must be above 50 degrees for cool growing plants, and at least 65 degrees for warm season annuals, according to Prosek.

For future reference, keep a record of indoor sowing dates, germination dates, length of indoor growing period, and transplanting dates.


Asparagus

Can I grow asparagus from seed? I saved the little red berries from my plants.

You can grow asparagus from seed. I have done so many times, but it takes three or more years for a crop, and growing from seed usually gives inferior plants. Better crops come from hybrid plants.

If the red berries from the female plant have dried over winter, there should be two or three black seeds inside. Clean them off and prepare your seed bed for planting.

Asparagus needs full sun and a sandy loam soil raked smooth. After the danger of frost is past, bury the seeds at a depth two times its diameter and keep the bed moist. In the third year you can lightly cut the pencil-thin stalks. There are often volunteers of female plants between rows you that can transplant. However, it is best to start asparagus by buying roots so you have a small crop the first year. Most varieties sold are male.


Pines in Winter

This past spring I planted a lacebark pine (Pinus bungeana) in full sun. As winter began, the angle of the sun’s rays has caused the tree to receive, at most, 4 hours of sun. What are sun requirements of evergreens in winter?

In general, pines adapt to the winter weather by becoming dormant, says Susan Eyre, Rich’s Foxwillow Pines Nursery, Woodstock. It is the freeze and thaw cycle that is hard on a plant, not the loss of sun hours. In a January thaw, sap rises and then freezes, which can cause the bark to crack, but plants usually recover.


Ground Cover Suggestions

I have a dampish area with poor grass and moss that I would like to change to ground cover, but if I have only one plant, won’t it be boring? Can I get rid of the grass in winter or early spring?

If we have a dry winter or spring, you can smother the grass with a heavy layer of newspapers held down by bricks or stones, or use a product that will kill the grass. Use it according to the label directions. Grass roots are very persistent, so you may have to dig out the remaining roots by hand. The moss will disappear as you aerate the soil and rake in organic material.

When your area is properly prepared, you will have a large choice of low-growing groundcovers.

Kim Schroeder, perennial buyer at Wasco Nursery and Garden Center, St. Charles, suggests the following: lily of the valley (Convallaria majalis), sweet woodruff (Galium odoratum), wild ginger (Asarum canadense), or European ginger (A. europaeum), vinca (Vinca minor), Tiarella, Astilbe-the cultivar ‘Perkio’ is shorter than Astilbe chinensis ‘Pumila’ and violas such as bird’s foot viola (Viola pedata) or sweet white viola (V. blanda).

These choices are not aggressive growers like goutweed (Aegopodium), which grows anywhere and is very difficult to eradicate. You can plant free form areas with one type and another alongside it as contrast. Most of these ground covers bloom at slightly different times to give you a spring-into-summer flowering season.


Winter Mulch

Must I mulch my garden and, if so, when is the best time to apply it? What are the best materials to use?

Perennial gardens usually come through the winter better when given some sort of protection, although many gardeners leave their established gardens unprotected save for deer netting to keep deer off newly emerging greens in spring. Plants new to your garden can be protected by mulch during the first winter and may not need it after that.

Mulch is used in winter not to keep the plants warm, but to keep the ground at an even temperature and prevent plants from heaving out of the soil during periods of alternate freezing and thawing. Thus it is applied after the ground freezes. If mulch is applied before the ground freezes, it can smother the plants.

The simplest mulch is a loose layer of oak leaves, which do not mat down and rot. Ground-up leaves are ideal, and even dried grass can be used. Or apply straw left over from Halloween decorating.

Use only a few inches of mulch and keep it light enough not to smother the plants. Deer netting helps to hold mulch in place until it is wet enough not to blow around. In spring, as soon as the plant starts to grow, remove the mulch gradually, a little at a time over several days. Don’t wait too long because if the shoots are too tall, you may damage them as you pull off the mulch. Work the mulch into the soil with a trowel afterwards.

Heucheras, astrantias and recently planted perennials may heave even if mulched. Push any dislodged plants back into the soil. Mulch also protects the evergreen rosettes of biennial hollyhock, foxglove, Canterbury bells and sweet William from snow and ice damage.


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.


Climbing Hydrangea

What does it take to make a climbing hydrangea flower? Ours was planted 3 years ago and is growing energetically. It’s in a protected nook near the patio and gets very little direct sunlight, but doesn’t act sun starved. We gave it a shot of slow release fertilizer on planting, and once since. Somewhat inadvertently it gets plenty of water, since the hose spigot is nearby and leaks, but drainage does not seem to be the problem. It now fully occupies an 8-foot trellis but shows no interest in flowering. Is it youth, lack of sun, too much or too little fertilizer, bugs, lack of pruning or what? When do these plants bloom and what conditions do they like?

Climbing hydrangea (Hydrangea anomala subsp. petiolaris) is a choice vine with rich, vigorous, dark green foliage, growing ultimately to 20 feet high and 10 feet wide. The extra moisture it gets is good, and it can bloom in shade. Brent Horvath, president and grower at Intrinsic Gardens, Hebron, has seen it blooming beautifully under a canopy of trees.

After weighing all the cultural factors you described, Horvath has concluded that your vine may be immature and will need a couple more years before it flowers. Climbing hydrangea matures very slowly, especially when it’s sold in 2 gallon containers.


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.


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