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Cycas

I have a cycas palm and am not sure how much direct sunlight or water it needs. It has light brown marks developing on the leaves. What is causing this, and how do I care for my plant?

Cycas palms or sago palms (Cycas revoluta) are tough house or patio plants. They are neither palms nor ferns but primitive cone-bearing relatives of conifers. A rosette of green feather-like leaves, 2 to 3 feet in height, grows from a central point at the top of a single trunk.

Cycas need bright light and should be kept relatively moist with weekly watering. However, prolonged rainy spells can cause fungal leaf spot disease.

“The shiny brown spots are probably caused by scale,” says Jeff Frohn, sales associate at Geimer Greenhouses, Long Grove. “It can be treated with fish oil, vegetable oil or an all-in-one insecticide spray,” adds Mike Geimer, owner, Geimer Greenhouses.


Staking Plants

I dislike staking perennials. Is there anything I can do to avoid it?

There are several techniques you can use to limit time spent on this chore, but it is difficult to totally

avoid staking some plants.

First and foremost, the old adage “right plant, right place” means full sun perennials need to be grown in full sun for tight upright growth. If they are too shaded, the plant will stretch or bend toward the sun and grow in a loose habit. Growing plants a little closer together also helps because it enables plants to support each other.

The best remedy to avoid staking is to cut some tall plants down by one-half in June. That will delay flowering in helenium, monarda, platycodon, chrysanthemum and aster, but the plants will remain upright. If you really want to eliminate cutting back, grow dwarf versions of these plants.”
Short, thin branches from forsythia or dogwood (known as “pea staking” in England) can be placed around the perimeter of newly emerging plants to help keep the stems upright. Some garden centers have begun selling bundles of branches for this purpose. In a short time, the shrub cuttings are covered by emerging shoots. This technique works well with fine foliage such as baby’s breath or flax.

There are numerous staking supports from bamboo to iron rebar rods. Wire staking supports are available in full, half and even quarter circles to support single stems. Peony hoops can be left in place over winter and will support not only peonies but boltonia, baptisia, and even errant tomatoes.

Some plants always need to be staked. Giant dahlia tubers need a heavy stake dug into the hole at planting time. That prized, single-stemmed iris, lily, or delphinium can get blasted in a storm, and then it’s too late to save it.

Remember: the time to stake plants is during the cooler days of spring when plants are growing rapidly and not on humid July days. Staking should be done unobtrusively and subtly for plants to retain their natural grace.


Gardening Trends

What are some trends in gardening you see becoming more prevalent in the next few years?

Nick Urhausen
Current gardening trends continue to explore a variety of annual shade alternatives. Consider begonias of all types, such as fibrous, hiemalis, nonstop, rex, tuberous and the trademarked Big series and Dragon Wing. For a tropical feel, caladiums, elephant ears, and banana plants are not only exotic but add an element of height. Lastly, the hundreds of coleus varieties, along with black and chartreuse sweet potato vines, are colorful, reliable, and rich in texture.

Diana Stoll
I believe choosing plants for butterflies, bees and other pollinators will be an important trend in 2015 as folks realize the important role they play in our environment. Growing fruits and vegetables will also remain an important focus of gardeners, especially those that can be grown in containers and small spaces. Low-maintenance plants, preferred by both aging and beginning gardeners, will be another trend to watch in 2015.

Anna Keesling
People are looking for “bee-safe” plants that are free of neonicotinoids and other harsh pesticides. Also, they want to do vegetable gardening with non-GMO varieties. Succulents are very hot. The indoor use of succulents in dish gardens is a no-brainer; they look cool, they’re so easy to care for and make great unique gifts. Ornamental kale and cabbage have become very popular for fall decorating.

Rich Hornbaker
The popularity of hostas has made gardeners realize how much fun it is to use foliage for color, so they are looking beyond flowers to the reds and purples of coral bells (Heuchera); the yellow fall bottlebrushes of Amsonia hubrichtii; and the great fall colors of shrubs such as Viburnum, oakleaf hydrangeas (H. quercifolia), witch hazel (Hamamelis) and trees such as seven son flower, (Hepticodium), Ginkgo and scarlet oak (Quercus coccinea).


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.


Rabbit-proof Plants

Which flowers can we plant that the bunnies won’t eat? My pansies and marigolds are all eaten.

Rabbits love crisp tasty plants as much as we do. Besides lettuce, they eat everything in the legume family, including beans, peas and sweet peas. Experienced gardeners know they have to protect these plants with row covers.

Annual pansies, nasturtiums, marigolds, impatiens, fibrous begonias, and lisianthus are some of their favorites, especially early in the growing season. Ageratum and sweet alyssum are two annuals rabbits do not eat.

Some perennials are not bothered by rabbits, says Kim Schroeder, perennial buyer, Wasco Nursery, St. Charles. These are English ivy, ajuga, yarrow, artemisia, lily-of-the-valley, foxglove, aconite, iris, peony, poppies, thyme, lychnis, lamb’s ears, ground-covering sedums, salvia and santolina.

For added protection, when you are setting out new plants, spray them at once with rabbit repellent so bunnies will learn to avoid that area, and re-spray after rain.


Azaleas

I received a beautiful flowering azalea plant during the holidays. I would like to continue growing it over winter. Will I be able to bring it into bloom next year?

Trying to get azaleas to flower in the home is difficult and time consuming because the light in a house is lower than that in the greenhouse where it originated. But if you would like to try to keep your plant growing, follow these directions.

To keep an azalea flowering after you get it, give it water-soluble acid fertilizer at quarter-strength. Keep it in a cool, shaded location, away from heat-releasing light bulbs or hot air vents.

After flowering, remove the withered flowers and keep the plant in a cool, sunny location. Water as needed to keep from wilting. In summer, sink the pot in the garden in a semi-shaded spot. Water and fertilize regularly. Acid fertilizers will help to maintain proper soil pH and keep the foliage from yellowing. Before July 1, shape the plant if needed. Keep the plant outdoors as long as possible in the fall. The plant may need protection from early light frosts but should be brought in before heavy frosts or freezes occur.

Once the plant is indoors, place it in a cool area, 40-50 degrees. An unheated porch, cold frame or similar area is good. Flower buds develop during the cold period. About 6-8 weeks of cold are needed for bud development. Do not fertilize during this time and only water enough to keep the plant from wilting. Buds should develop and swell. In January, move the plant into a cool sunny area, about 60 degrees. Flowering should begin in a few weeks. If temperatures are excessively high during this period, buds often develop poorly and new shoots will grow right past the buds, hiding them. Additional humidity is helpful to keep the calyx on the flower moist and easier to open.

Even if your plant doesn’t rebloom, all is not lost. Azaleas are known to be air purifiers.


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.


Birch Trees

I’d like to plant a white bark birch in front of my home in my sunny front yard. What can you tell me about Betula utilis var. Jacquemontii?

The birch, Betula utilis var. Jacquemontii is a tall, narrow tree (to 100 feet) with very white bark that’s native to India. It is subject to borers. The popular weeping white bark birch, B. pendula is also subject to borers in our climate and is not a suitable choice.

“There are better birch choices, so choose what grows well in our area,” advises Ken Morris, vice president of Spring Bluff Nursery in Sugar Grove. Two trees resistant to borers are the paper or canoe birch and the river birch.

Canoe or paper birch (B. papyrifera) has a stout trunk with creamy white bark that peels off in papery layers. It is native to North America. It is the first paper birch bred to resist the bronze birch borer, but it still needs to be monitored and sprayed yearly for the borers. A good cultivar is ‘Renaissance Reflection.’

River birch (B. nigra), native to the eastern United States, is fast growing when young. It can reach more than 50 feet in height. Its bark is a smooth, shiny apricot and, when mature, flakes and curls in cinnamon strips. It tolerates slow drainage and is also resistant to borers. “It’s pretty tough, good and sturdy,” says Morris.

The cultivar ‘Heritage’ was introduced to much acclaim around 15 years ago.

Birch trees need moisture. Do not allow your tree to dry out in your sunny site.


Pumpkins

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?

The longer the fruit is on the vine, the greater the chance it will rot. By September its size is apparent, and it turns orange. It is best to plant pumpkins in different soil each year or every two years, according to Sue Murdock, manager, Goebbert’s Pumpkin Farm, South Barrington.

The size and use of pumpkins is determined by the seed you buy. ‘Atlantic Giant’ produces fruits that weigh hundreds of pounds. A better choice is to grow ‘Howden’. It bears well-shaped 10 to 20-pound fruits, the perfect size for jack-o-lanterns. ‘New England Pie’ is the standard for pies with smooth, bright orange flesh. ‘Wee-B-Little’ is a miniature round pumpkin bearing 3- to 4-inch fruit useful for table decorations and suitable for tiny hands.


Variegated Sedum

I have a large variegated sedum with pink flowers that I have had for years. I noticed that it has started to send up some all-green shoots. Why is it doing this and how can I keep my plant variegated?

All variegated plants contain a combination of green cells with chlorophyll and white tissue with no chlorophyll, which produces the green and white effect. Variegated plants are genetically unstable, so sometimes the tissues revert to all-green cells and send up solid green shoots from the base of the plant. Because these shoots contain more chlorophyll than the variegated tissue, they are more vigorous. Thus they can quickly overrun a plant, according to Hortech, a developer and grower of sedums.

Cut the green shoots off at the base of the plant as soon as you see them. It is possible you have induced vigorous growth by giving the plant too much high-nitrogen fertilizer, so it would be wise not to fertilize. It sometimes helps to divide your plant and then choose the most variegated stems for a new plant. Since your sedum, a cultivar of Sedum spectabile, is such a rapid grower, it will quickly become a new clump after division. Newer named cultivars are more genetically stable and do not have this problem.


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questions

When is the best time to cut back hydrangeas? How far do I cut them back?

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.

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