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.
Now that bedding impatiens (I. walleriana) are not recommended because of impatiens downy mildew, what are three good annuals for shade?
Chris Williams, production manager, K&W Greenery, Janesville, Wisc.
I like New Guinea Impatiens. They make nice bushy plants that are full of large colorful flowers and are easy to grow. You also get a large color selection with New Guineas. The SunPatiens and Bounce impatiens are fairly new plants, and they are recommended for sun as well as shade. Then there’s coleus. Who doesn’t like its colorful foliage? Many varieties grow upright, but others also spread. Torenia, also known as wishbone flower, has trumpet-like flowers of white, yellow, rose and purple that cover nicely mounded, low-growing plants.
Karen Wedel, manager of the outdoor floral department, Wedel’s Nursery, Garden Center, Kalamazoo, Mich.
One of my favorites is begonia. Tuberous varieties have large colorful blooms; wax begonias are good for mass planting. I’m also a fan of the big leaf, 16-20 inch tall Whopper series with large waxy leaves and summer-long flowers.
Another idea is coleus and caladiums. They come in different foliage colors, work great in gardens and containers. They are both also easy-care.
Finally, torenia or wishbone flower, named for the small “wishbone” inside the mouth of the pink, yellow or blue-purple flowers. Blooms all summer. Some varieties will trail.
Kevin DeBoer, manager, Big John’s Farm Market and Greenhouse, Chicago Heights
My favorite is Dragon Wing begonias. They’re usually sold in 4½ inch pots or hanging baskets. At my house I removed them from the baskets, then planted them in the ground in full shade. They turned out awesome! Plain wax leaf begonias are also good.
In addition, I like coleus. They don’t produce flowers, but they have many different vibrant leaf colors. In full shade New Guinea Impatiens will flower sparingly, but if you put them in some sun, they will flower more.
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.
We all seem to plant the basic herbs like basil, rosemary and parsley. What suggestions can you offer for more exotic herbs that I could add to my garden to spice things up both for cooking and adding interest/beauty to my landscape?
Ron Peterson, head grower, Milaegers Garden Center, Racine, Wisc.
I think lemon grass (Cymbopogon citratus) would be a good candidate for landscape interest and culinary use; it is even reported to have more mosquito control attributes than citronella. It is a warm season annual grass that grows quickly and is used in teas and Thai cooking to add a lemony flavor without the acidity of lemon juice. Stevia is a natural sweetener option for those trying to avoid added sugar. There is also a mint called Berries and Cream which merges peppermint with berry flavors for a unique twist on the traditional mint options.
Lisa Hilgenberg, horticulturist, Chicago Botanic Garden, Glencoe
Golden lemon thyme (Thymus x citriodorus) adds good citrus flavor to dishes and tea. The 8-inch tall cultivar ‘Aureus’ makes a good edging paired with Salvia officinalis ‘Icterina’. The chartreuse ‘Lime’ shines in dark garden corners.
Red shiso (Perilla frutescens) has frilly garnet red leaves, edible flowers and a spicy cinnamon/clover flavor. Papalo (Porophyllum ruderale) has a taste between arugula and cilantro. Plant once cilantro bolts to seed. Steely blue foliage up to 5 feet tall.
Joe Heidgen, co-owner, Shady Hill Gardens, Elburn
A plant that is often included with the popular herbs that gardeners know at Shady Hill is the scented geranium. It doesn’t look anything like a garden geranium, but it has a wide range of fragrances, as well as varying leaf shapes and colors. The fragrances may be lemon, rose, pine, ginger, lime, balsam or apple. It can be used in cooking and also in potpourri and sachets. Some scented geraniums are upright, some cascading, but all are unique and quite easy to grow. They are ideal for planters.
Kevin DeBoer, manager, Big John’s Farm Market, Chicago Heights
Onion or garlic chives can be grown and cut for use in potatoes and eggs. We also have five different types of mint that can be grown and used for mojito, flavoring water and teas. Some varieties such as pineapple mint are attractive and add beauty to the garden. Thymes such as English and lemon can be used in pasta and in marinades for grilling. A good marinade for meat can be made from thyme, rosemary, sage, Italian olive oil and pepper.
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.
I purchased some pre-chilled hyacinths and tulips for forcing but there were no directions with them. Does this mean I don’t have to chill them in the refrigerator, and will they just bloom in the house any time during the winter? The last batch of bulbs became moldy in the refrigerator.
Using pre-chilled bulbs avoids the 12- to 14- week cold treatment that bulbs need for indoor blooming. However, you need to pot up the bulbs in a loose potting mix. Do not cover the bulbs in plastic wrap or paper bags. It will still take 3 or 4 weeks of cold for roots to appear.
Hyacinths kept cool do not need to be potted. They can sprout roots in a saucer of water with the bulb held in place by stones. Check the water level and make sure it just touches the base of the bulb and add water as needed.
The bulbs can be forced as soon as you see roots, or you can hold them in the cold temperature to space out the bud development. Place rooted bulbs in bright light in a cool room, and watch for buds. Rotate the plant so the flowering stem will be erect. “Your previous bulbs rotted because they were not potted up,” says Lori Harms, greenhouse manager, Countryside Nursery, Crystal Lake.
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.
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.
I’d like to block an unattractive view of my neighbor’s house/yard. What are some good plant/tree choices to hide unattractive views?
John Eskandari, owner, The Urban Plantsman, Chicago
Two evergreens for sun are Thuja occientalis ‘Wintergreen’ and Picea pungens ‘Fastigiata’. Both are moderate to fast growers. For shadier locations, Picea abies ‘Cuppressina’ does remarkably well.
A deciduous tree that would work nicely is Fagus sylvatica ‘Dawyck’. It comes in green, gold, red and purple leaved varieties. They work well in shadier spots but the red and purple leaves are less intense in shade.
In smaller areas, I like Amelanchier laevis ‘Cumulus’. It’s a more upright form of serviceberry providing nice spring blooms, edible berries, and golden fall color. It is adaptable to both sun and shade.
Chrissie Sieff, nursery manager, Platt Hill Nursery, Bloomingdale
Whenever I am asked this question, my customers usually have something in mind such as ‘Emerald Green’ arborvitae (Thuja occidentalis ’Emerald Green’, sometimes labeled ‘Smaragd’). They want a green wall, and they want it instantly! Our dead plant return rate is high on this item, so I try to steer them to hardier choices, such as Viburnum nudum ‘Winterthur’ or Syringa pubescens subsp. patula ‘Miss Kim’.
A strategically placed tree can also do the trick. I love katsura tree (Cercidiphyllum japonicum), river birch (Betula nigra), serviceberry (Amelanchier), and ‘Ivory Silk’ tree lilacs. As you can tell, I’m not a big fan of evergreens.
Andy Wedel, part owner, Wedel’s Nursery, Florist & Garden Center, Kalamazoo, MI
Arborvitae (Thuja spp.) is the first plant we think of, but there are others. It’s hard to pick just one. Fine Line buckthorn (Rhamnus frangula ‘Ron Williams’) is a columnar-shaped deciduous shrub with yellow fall color. Evergreen, drought-tolerant upright junipers such as Juniperus chinensis ‘Blue Point’ are great in sunny spots. Some other columnar trees include ‘Crimson Sentry’ maple (Acer platanoides ‘Crimson Sentry’), Red Fox katsura (Cercidiphyllum japonicum ‘Rotfuchs’), and columnar hornbeam (Carpinus spp., cvs.).
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.
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’d like to know the secret to growing a decent-sized pumpkin for jack-o-lanterns for the grandkids and for decorating. My experience in recent years is that they get about as big as a basketball and then begin to rot. What am I doing wrong?
Our Russian sage (Perovskia) is full and bountiful but will not stay upright. Is there anything we can do? Is there a way to split some off when it has outgrown its space? Should it be trimmed back in fall or spring?