In the Garden
Ralph Purkhiser, Purdue University Master Gardener
Autumn will arrive on Sunday, September 22 at 8:44 AM Eastern Daylight Saving Time. However, it appears that summer just does not want to let go. Warm temperatures remain in the forecast. A tropical system may bring some chance of much-needed rain to the Hoosier Hills this week, but cooler temperatures are not expected, with highs expected to be near 90 degrees.
If you visit garden centers, you may see signs claiming that fall is for planting. Normally, that is so, but the weather conditions need to be more fall-like to really be good for planting. Perennials, trees and shrubs may all be planted in the fall, but timing is important. For most plants, they need to be planted early enough to allow good root establishment before the ground freezes. Without good root establishment, the plant may suffer from heaving during the freeze-thaw cycles typical of an Indiana winter. It the roots are heaved out of the ground, they may freeze during the next cold snap. Even if the cold does not kill the plant, the heaved roots will become desiccated if there is little snow cover.
Moisture is another important factor in fall planting. Soil moisture levels are low after several weeks of drought, and plants must have moisture to get established. Supplemental watering will almost certainly be necessary, even if we get some rain. Watering deeply is necessary. Plants that are watered sparingly will develop feeder roots near the surface to take advantage of the water sprinkled on the soil surface. Letting the water soak deep into the soil will make the roots grow to seek that moisture. It is better to water deeply and less frequently. On the other hand, some plants will suffer if we get a lot of moisture in the winter. Such plants should be planted in areas with good drainage, such as on banks.
Garden centers will soon be marking down the plants, and it is hard to pass up bargains, especially for plantaholics like me. I already have a nursery area of plants I have purchased, and I am sure I will find more as I visit garden centers this fall. The truth of the matter is most nurseries do not have the capacity to over-winter plants in pots. While some plants that are especially cold hardy may survive, more marginal plants need to be in the ground. Big-box stores do not overwinter any of their plants, so they will either discount them or throw them in the dumpsters. However, a bargain is not truly a bargain if you are just going to let the plant die.
Plants set out in the fall will need special attention through the winter. While our winters tend to be wet, if we do not get normal precipitation, you may need to water plants in the winter. This should be done on days when the ground is not frozen. You should check on your plants frequently to see if they need water. You also need to watch for heaving of the root ball, and take steps to get the roots back in the soil if heaving occurs. One way to prevent heaving is to apply a couple of inches of an organic mulch after the ground is frozen. This will insulate the soil and keep it from thawing.
Over the next couple of weeks, I will be trying to plant some of the shrubs and perennials I have purchased. It will be a busy time, as I will also be preparing to host my Century Celebration open garden event on Saturday, September 28. Come on by Sandhill Gardens to help celebrate 100 years of my family’s gardening here. We will begin with a plant exchange at 10 AM, and there will be some gardening talks and demonstrations throughout the day. It will be pretty informal, but I invite you to come and see plants that my maternal grandmother, Bertha Hooten, set out in the fall of 1924. She must have done it right, as many of them are still growing in the same locations a century later. I hope to see you here.