Zone 4 or Zone 5?

Leif’s article for the May 5th Northfield News shares our “frustration” this spring with micro-environments at home in our shade garden. We are pulling out hundreds of little maple sprouts!

‘A nice stretch of spring weather has had people very active in yards and gardens, and farmers making substantial progress planting the corn crop. During the big Easter chill a few weeks ago, it hardly seemed possible, but spring has indeed arrived in Southern Minnesota.

While the average date of the last frost has historically been between May 10th and May 15th, it may be fairly safe to set out your bedding plants now. The 15 day Accu-weather long range forecast we checked does not predict any sub-freezing temperatures between May 2nd and the 17th!

If you do have frost sensitive plants in the garden be prepared to cover with old sheets and other light materials should forecasts change at some point. Also, if your gardens are in a low lying area where cold air slides in from surrounding higher land, know that you could experience frost when twin Cities forecasts are calling for low temperatures of about 36 to 38 degrees.

This brings to mind the subject of micro environments. Usually this comes up when considering placement of a Zone 5 plant into our Zone 4 climate. If you can select a location that has protection from winter winds, the worst extremes of winter cold, and protection from intense winter sunlight, a Zone 5 plant may prosper.

When working in our shade garden recently, Deb and I came across a striking example of a temporary micro-environment. In one of our hosta beds, a semi circle of hosta are planted a couple of feet apart. The spent foliage and stems of the hosta clumps provided a place for sugar maple seeds to collect as the fall and winter winds whipped leaves and seeds back and forth for six months.

The mulched areas next to the hosta clumps were smooth, with little to hold and cover the maple seeds. Leave that lodged in the hosta stems over the top of the maple seeds, protected the seeds from excessive drying, and a very favorable environment for germination once spring arrived.

The result is a semi-circle of clumps of sugar maple seedlings coming up right where the hosta are, and just before the spring growth of the hosta begin. Unfortunately, we will have quite a job hand weeding out the seedlings since we have over 250 varieties of hosta and every single clump has a cluster of tiny maple trees in its crown.

Micro environments exist all over the place. Almost every piece of property has micro environments. More sunlight or greater shade produces different micro environments. Rich undisturbed native soil or alkaline clay placed alongside a foundation for backfill right in the location of a future planting bed produces micro-environments of different soil quality..

A layer of sand concentrated in a small area where it had been stockpiled during construction can cause a few plants in a hedge to grow differently, perhaps more slowly. An area with poor drainage is another micro-environment. Protection from or exposure to wind is another part of the existence of micro-environments.

Many complex and inter-related factors can interact to form a whole range of varied micro-environments. Pollution creates micro-environments. One creative part of successful gardening is to gain a good understanding of your property so you can identify your various micro-environments and match the best plants or uses to these spots.

Disappointment is likely when forcing a plant into a micro-environment where it is poorly suited. On the other hand that same location can produce very good plant growth if a variety is placed there that takes advantage of the site conditions.

A good example is a spot with poor drainage where sunlight is full day. A lilac shrubs planted there struggles for a couple of seasons and then dies. A pussy willow, red twigged dogwood or alder would be likely to grow very well in the same spot since their root systems are adapted to take advantage of high moisture levels. For gardening success, match your micro-environments to varieties that like the conditions your site offers.

Plant Spotlight: Flowering Crabs. These spring show stoppers are available in dozens of varieties, with many newer varieties that are disease resistant, flower heavily, and sport colorful fruit throughout the fall and winter. Quite a few varieties hang onto their fruit all winter, so that when it does finally fall as buds are swelling the next spring, the fruit is dried up and cleanup is easy. For ease of maintenance, plant in landscape beds with organic mulch rather than rock mulch. Over lawns the cleanup is almost a non-issue with these new varieties that have persistent fruit. For small spaces, quite a few dwarf varieties are available that will stay in scale with the area. Excellent disease resistant varieties that look good all season are Red Jewel, Sugar Tyme, Prairiefire, Royal Raindrops, Tina, Lancelot, Coralburst, Louisa and Harvest Gold.’

(The picture above is of the blossoms on the Prairie Rose Flowering Crab that I took last summer!)