Extension Communications 3614 Administrative Services Building Ames, Iowa 50011-3614 (515) 294-9915

10/6/03

Contacts:
James Romer, Horticulture, (515) 294-2336, jromer@iastate.edu
Jean McGuire, Continuing Education and Communication Services, (515) 294-7033, jmcguire@iastate.edu

Yard and Garden Column for the Week Beginning Oct. 10, 2003

Fall Back With Dr. Grow-It-All

By James Romer
Extension Horticulture Specialist
Iowa State University

Dear Dr. Grow-it-All:
I've got this brother-in-law who think he knows it all. You know, the type that if he really did know all the things he was talking about, he would be 600 years old! He told me that I could still put down grass seed this fall and seed that didn't come up would go dormant and come up next spring. He also said that I could put down crabgrass preventer on top of the newly seeded area in the spring as well. Does this seem right to you?
Late in Early

Dear Late:
I see your brother-in-law is one that likes to have his cake and eat it too! It would be nice to do everything he mentioned. However, no one knows the number of warm days to trigger germination of the grass seed we have left. In Iowa, October and November are months that can be extremely nice or full of snow days. Sod can usually be laid until early to mid November. Wait until April to sow grass seed. Any of the grass seed that he said would go dormant over the winter and germinate in the spring would be killed by the crabgrass preventer. Most preemergence herbicides (crabgrass preventer) will prevent the germination of crabgrass and turf grass seeds. Tupersan (siduron) is a pre-emergence herbicide that can be applied to newly seeded lawns. You need to choose whether to put down grass seed or apply crabgrass preventer next spring.

Dear Dr. Grow-It-All:
My neighbor gave me some summer flowering bulbs to plant in May. I had great success growing the cannas and dahlias given to me, but Jack Frost has made an appearance in my garden. What do I do to save them?
Freezing in Fremont

Dear Freezing,
Cannas are the easier of the two to over winter. The most critical factor in the success or failure of storing canna rhizomes is moisture. If they are packed while still moist or wet to the touch, rotting will occur. Therefore, it is best to lift the rhizomes and place in a well-ventilated location to dry for a couple days. Then place the clumps into a paper sack, box or bucket. Store the cannas in a cool (40 degrees to 50 degrees F), dark location and keep them there until danger of frost has passed in the spring. Check the containers periodically to ensure rot has not started.

Dahlias need a little more attention. After a killing frost has destroyed the above ground foliage, remove the above ground parts and let the tuberous roots sit in the ground for 1 to 2 weeks. This gives the roots a chance to cure before their removal from the soil. If the cultivar name is important, write the name of each plant on a tag or label before digging the dahlias. They all look similar after being dug.

Using a spade or potato fork, carefully lift each clump out of the ground and immediately attach its identification tag to one of the tubers. Next, wash off as much of the soil as possible. Allow the tubers to dry to the touch (usually 1 or 2 days), and then cut the stems back to the crown. Place the tubers upside down and cover with vermiculite, peat moss, wood shavings or sand. Store in a cool and dark location.

Dear Dr. Grow-It-All:
A good friend of mine told me that to kill Creeping Charlie, all I needed to do was to mix up Borax and apply it to the plants. She showed me areas that had been treated, and I've got to tell you it looked like it worked. Since she couldn't remember the exact mixture, I was wondering if you could tell me the correct concentration. I bought several boxes so I won't run out.
Borax Bound in Hanlontown

Dear Borax Bound:
Before you buy all of the borax in town, there are some items you need to know. Iowa State University did some preliminary research on the effect of borax on ground ivy or creeping Charlie. Borax contains the nutrient boron. All plants require small amounts of boron for growth. However, large amounts of boron in the soil are toxic to many plants. Creeping Charlie is more sensitive to boron than the cool season grasses.

If properly applied, borax will destroy the ground ivy without killing the turf grass. Sometimes the grass will also die in an area that has been over treated. Borax is not labeled for use as a weed killer. Consider using a broadleaf weed killer that contains the active ingredient dicamba. This is the best time of year to rid your lawn of this invasive ground ivy. Make two applications about 14 days apart and relax. It will give you more time to wash laundry with all those boxes of Borax!

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Editors: There is no photo available for this week's column.

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