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PRAIRIE GARDENER: Late summer flowers find their place in the sun

Late August can best be described as the grand finale of the gardening season. The sweet corn, tomatoes and other vegetables are at their peak. Frost danger is several weeks away. Winter is still well down the road.

Late August can best be described as the grand finale of the gardening season. The sweet corn, tomatoes and other vegetables are at their peak. Frost danger is several weeks away. Winter is still well down the road.

But as we go into the final lap of summer, our flower beds may be looking somewhat shopworn. The annuals are probably struggling now and the peonies, irises and other mid-summer bloomers are but a memory. It's too early for most fall-blooming mums, too.

So, veteran gardeners fill in this gap with summer-flowering roots, tubers and corms. The best known of these are gladioluses, dahlias and cannas. There are others as well, including calla lilies, which the Prairie Gardener has been experimenting with in his garden..

The culture practices for the three major late summer bloomers are nearly the same. They prefer a sunny location with friable, fertile soil. Rotted compost or manure along with peat moss can be worked into the soil prior to planting. Plow, till or spade your garden spot as you would with any other garden seed or plants.

Flower options


Gladioluses, dahlias and cannas are planted directly into the garden once the danger of frost has ended. Gardeners can pot up and start dahlias and cannas several weeks earlier and raise them indoors. This will hasten blooming. A common problem with some of the late bloomers in that they are just getting ready to flower when frost strikes in autumn.

All of these tender plants have to be dug after a killing frost to retrieve the roots, tubers or corms. These have to be carefully cured before being placed in a cool, moist basement for winter storage. Then in the spring they have be taken out and replanted. Unfortunately, this takes time which many gardeners can't spare. But these plants do pay large dividends in terms of beauty. The colors are very rich and vivid, perfect for that last hurrah of summer.

- Gladiolus: This flower comes in a wide selection of colors including white, cream, yellow, orange, rose, lavender and salmon, to name just a few. Stalks can grow up to 5 feet tall, bearing 12 to 14 blossoms at a time. These flowers are especially popular for weddings and other formal occasions in late summer.

Glads often tip over in the garden if we have high winds. You can cover the corms or bulbs with 2 inches of soil at planting. Then place additional soil around the stalks later, eventually hilling up about 6 inches around the plants. Drainage is important. If bugs are a problem, spray with Malathion, Sevin or Orthene every two days to three weeks as needed.

In early October, you can dig your glads. Save the tiny cormels that appear at the base of the corm.for future planting. Remove any dirt and the old corm, which is shriveled and at the base of the new corm. Curing takes seven to 10 days. Then prepare for winter storage by applying a corm dust and place on trays or mesh bags in the coldest part of the basement.

- Dahlias: If you have never grown dahlias, next spring is a good time to start. Popularity has increased the assortment available and few flowers offer more bang for the buck.

Native to Mexico, dahlias are sensitive to frost and should not be planted outdoors until the threat of frost has passed. Dahlias come in many for forms including tiny bedding plants or the large bush forms. Flower forms also vary from the large dinner plate kinds to the small pompons, singles and dwarfs. Avoid high-nitrogen fertilizers. Dahlias love mulch, which cools their tubers and conserves moisture.

After a killing frost, dig up plant. Shake off soil from root clump and cut off the stalks. Cure in a sunny, dry area for several days before storing in the basement. Plastic bags, filled with peat moss, work well. The roots will shrivel if too dry. Keep bags slightly open to allow air t o circulate. Check for white mold during first two months or more of storage. If you have a problem, remove from bag and dry several more days before repacking and storing.


- Cannas: Native to the tropics, cannas are best adapted to warm-to hot-summers. An old favorite, they can add a tropical touch to the right place. Spikes of large, showy flowers in a range of sizes, shapes and colors bloom on 3 to 6-feet tall spikes. Cannas are most effective in groups of single colors against a plan background. These plants work best if started early indoors. After a killing frost, prepare for winter storage as you would dahlias. They prefer even more moist conditions than dahlias tubers. Use the plastic bag, peat moss combination of storage, but check frequently for spoilage. Leave bag slightly open to allow air movement. The coldest place in your basement works best.

(Two years ago, The Prairie Gardener confessed to the 13th District of the Minnesota Horticulture Society at its Badger, Minn., meeting that he had given up on cannas. A gardener attending purchased some for him and the Prairie Gardener's luck has changed for the better. Thanks.)

Drying flowers

The hydrangeas are especially beautiful this year, and several gardeners have inquired how they could be preserved along with other flowers for winter bouquets. Drying flowers is easy. The most common is to simply dry them. However, other methods are to use glycerin, sand drying or to use homemade agents such as Borax, corn meal and salt and silica gels.

Hydrangeas and other summer flowers, such as straw flowers and forms of celosia, respond well to air drying. Pick flowers at the height of their bloom before they begin to fade and at mid-day, not after a rainfall. Immediately after picking, hang flowers upside down on a line out of direct sunlight. Attics, closets and pantries work best; basements, porches, garages and other damp places are not.

Divide the flowers into small bunches to avoid crowding or crushing. The stems of of the flowers c an be tied together with twine, wire, pipe cleaners, rubber bands or anything that will hold them securely yet not break the stems. Time to dry can be a couple of weeks or more depending on the moisture content of the flowers and the ambient humidity. Store dried plant material in a dry, dark place until ready to arrange.

Dog blight

If you are a dog owner, you probably have yellow spots on your lawn that look dead. Known as dog blight, these spots are where dogs repeatedly urinate. Nitrogen in the urine kills grass just as an overdose of fertilizer would. If you look closely, you will notice a central area of dead grass surrounded by tufts of lush, green grass..


To restore a yard with dog blight, soak the area with water to dilute nitrogen in the soil. Then use a lawn repair kit (grass seed and mulch) found at most garden and hardware stores. Some products or kits are designed just for dog blight. Or, you can till up the area after soaking, adding some dirt and grass seed. Keep areas moist while seeds germinate and root. Burlap or mulch will conserve moisture. Small patches, the size of your fist, don't need to be reseeded because they will fill in by themselves. Dog runs or fenced-in areas can help to alleviate the problem.

Garden course

The North Dakota Extension Service in Grand Forks County will host a Master Gardener Course via video conference from 8:30 a.m. to 12:30 p.m. Fridays from Sept. 5 through Oct. 24 in the Grand Forks County Extension Office, 151 S. Fourth St. For more information, call (701) 780-8229.

For those gardeners who graduate and provide 48 volunteer hours, the fee is $100 including materials. The other option is a $200 fee requiring no commitment. Seating is limited, so an early application is a must.

Koehler is the Herald's garden columnist. His column is published every other Saturday. Send garden questions to him in care of the Grand Forks Herald, Box 6008, Grand Forks ND 58206-6008. Tune in the weekly gardening radio show airing at 4:10 p.m. Thursdays on KNOX 1310 (A.M.)

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