TIMELY GARDEN TIPS FROM

OVER THE GARDEN FENCE

August 20, 2005

This summer's weather has been so consistently sunny and warm that many of us probably haven't noticed the "growing season clock" is continuing to move ahead. Today is the 20th of August and there are many signs that autumn is just around the corner. Football practice has begun, we Tiger fans have little left but to hope for more wins next season, chrysanthemums are showing some color, fall anemonies brighten many perennial gardens, and swamp scarlet maples are beginning their show.

The following notes should be helpful in keeping lawns, gardens, and landscape plants looking their best.

Fall webworm tents are making quite a comeback this year. Their ugly webs and nests infest many landscape trees including crabapple, cherry, and walnut. Fall webworms are easily controlled with one spray of Carbaryl or all-natural Spinosad.

Is there a magnolia or tulip tree in your landscape? If so, be sure to examine it closely for scale infestation. Scale insects are very numerous on magnolia and tulip trees in many neighborhoods. Scale can cause the death of branches. Scale insects also leave sticky drips of honeydew on everything under the tree, which then attracts a ton of other insects to the infected area like yellow jackets, bees, and ants. Control scale with sprays of Safe-T-Side Horticultural Oil mixed with Malathion. Usually, scale-infested plants are covered with black mildew growing on the honeydew. One spray of Halt Fungicide will clean up the mildew.

This week's MSU Extension Bulletin expands on the necessity of proper soil drainage in our landscape and its impact on plants.

Plants need water. So why is too much water such an issue? In addition to water, plant roots need oxygen. If the pore spaces in the soil are filled with water, roots are not able to respire and therefore are unable to grow or take up water and nutrients. This is why some symptoms of excessive water are similar to symptoms of drought or nutrient deficiencies. Excessively wet soil can also lead to problems with root rot.

Excessively wet soils may be caused by one or a combination of several factors, one being a lack of surface drainage. This refers to the inability of run-off water to leave the site. Surface grading may eliminate the problem. As a general rule, a slope of at least 2% should be provided to ensure runoff.

Too wet soil may also be caused by impervious layers. Even though the soil near the surface may be course and permit infiltration, clay layers or hard pans may limit drainage into the subsoil. The remedy may be to break up the hard pan. However, sub-surface hard pans can reform over time and drain tiles may still be the best long-term solution.

Another cause of excessively wet soil is a high water table. In some cases, saturated soils cannot be avoided due to the response of a high water table rather that inadequate surface drainage. Sub-surface drainage can eliminate the problem, but another long-term solution is to select wetland plants adapted to wet conditions.

When planning a new garden, installing new landscape plants, or starting a new lawn, consider how well the site drains and the composition of the soil. If soil is heavy, incorporate clay soil conditioner into the top six inches when developing a new lawn. Established lawns suffering from compacted soil can be improved by core aerating, then adding clay soil conditioner and gypsum.

Confronting poorly drained soil when developing flower or vegetable beds can be challenging. The easiest way around the problem is to build raised beds. Use Allan Wall Blocks, three blocks high, fill with Wedel's special soil mix and presto! you've got the perfect growing area.

When planting larger deciduous trees, evergreens, and shrubs, be sure to dig deep enough to break the hard pan at the bottom of the planting hole to prevent excess water build-up. Larger plants should also be planted slightly higher than grade to promote proper drainage.

Before your next planting project, be sure to provide proper water drainage. There will be fewer plants to be replaced as well as faster growth.

Another MSU note this one about pesky crabgrass. Make space on the trophy shelf 2005 will go down as a banner crabgrass year. In what is shaping up to be one of the hottest summers in 100 years, lawn weeds are "making hay while the sun shines." Why so much crabgrass this year? Because of a very dry May, crabgrass did not germinate at the usual time. By the time we did get good crabgrass germinating conditions, the pre-emergence controls applied in early spring were not as effective. Think of this year as the 100-year flood event, only for weeds. Crabgrass, white clover, chicory, buckhorn plantain, and wild carrot are out in record numbers. Most new lawn seedings from this spring are completely overrun with weeds. If the weeds haven't suffocated those tender new turf stands, diseases such as pythium and brown patch probably have.

Carefully examining my own lawn recently revealed no crabgrass plants. My proven method for a crabgrass-free lawn is as follows. Number one don't apply crabgrass preventers before the last week in April. I always apply Scotts Step 1 the first week in May.

Number two - don't allow the turf to become stressed. Begin irrigating early. Dry weather this spring stressed and thinned many lawns, which allowed for broadleaf weeds and crabgrass to colonize. This rule of thumb works; apply one-half inch of water every three to four days.

Number three for a crabgrass-free lawn mow high. Lawns cut at 1 to 2 inches will have far more weeds than those cut at 3 to 3 inches.

Number four keep broadleaf weeds controlled with spot sprays of Weed Free Zone.

Number five fertilize. Fertilize with iron-rich Lawn Pro Super Turf Builder in mid-May and August. Use Turf Nurture Organic Fertilizer in June and July and apply Lawn Pro Super Winterizer in October.