For years the landscape industry has been utilizing the tag line “Fall is for Planting” as their narrative to encourage late season gardening activities. Unfortunately, for many of the folks I interact with, there is a good deal of confusion about exactly what this phrase means. With the lofty goal of setting the record straight (once and for all time) on the do’s and don’ts of fall planting, let’s take a closer look at some late season landscaping tricks and tips.
First, let us define fall when it pertains to our local gardening season. Mid-August marks the beginning of our fall season due in large part to the likelihood of more consistent cooler temperatures along with more predictable rainfall. The combination of cool air, moist and (most importantly) warm soil conditions favors most all plant growth. This is the ideal time for planting grass seed as well as transplanting many of your hardy perennials and evergreens trees/ shrubs. Most deciduous plants (plants that lose their leaves in winter) will prefer to be transplanted later in the fall once fully dormant.
Please take note; there is a BIG difference between planting, transplanting and harvesting. You can plant a tree/shrub/perennial at any time as long as the ground is not saturated or frozen. The seasonal limitations are directed towards plants actively growing in the ground that need to be moved or harvested. This is a disruptive activity under ideal timing and conditions but can be catastrophic when done during the incorrect time of year. When trees or shrubs are dug (harvested) from the ground, a large amount of their root system is lost and this causes stress that is generally recovered from provided the correct timing and techniques are adhered to. What this all means is that a tree or shrub that is either in a pot or already harvested (above-ground) is not subject to seasonal stress and can be planted at any time.
Of course there are exceptions and guidelines to follow with everything we do and fall planting is no different. For perennials we generally like to have our plantings completed before mid-October to ensure they will have adequate time to “root in” before the cold winter weather arrives. Does planting later mean certain death for these plants? Surely not! These dates are based on average weather conditions (nothing seems average any more) so, yes we often find ourselves planting late into fall with much more success than failure. Another general “perennial” rule to follow is to divide/transplant fall blooming perennials in spring and spring blooming in fall. (Again, before mid-October) This is another rule we find ourselves breaking in many cases. There are many perennial plants that are simply not particular as to when their growth is disrupted.
Trees and shrubs also have some seasonal details when it comes to fall plantings. Many trees are sensitive to fall harvesting/transplanting. These include (but are not limited to) Dogwood (Cornus), Redbud (Cercis), Birch (Betula), Beech (Fagus), Willow (Salix), Ginko, Sweetgum (Liquidambar), Blackgum (Nyssa), Blooming Pear (Pyrus), Bald Cypress (Taxodium) and Zelkova. Again, potted plants or trees harvested earlier in the season are not as susceptible as those growing in the ground requiring fall digging. We try to have all Arborvitae and Cedar plantings completed before mid-October as well as Roses and evergreen groundcovers (Ivy, Pachysandra, and Myrtle).
Timing can also be important when planting fall lawns/grass. It is always best to plant grass seed in early fall (mid-late August) but that isn’t always possible. September remains a very good time for planting grass seed but once we get into October, successful planting can have its obstacles. To plant grass seed well you need dry conditions to work the soil and integrate the seed into the earth. Dry soil conditions become less likely the later we get into the fall. Keeping falling leaves off newly planted grass can also be a challenge in October without walking on (and damaging) emerging grass plants. These grass babies can be damaged by severe cold temperatures as well if we are unlucky enough to have an early blast of frigid fall weather. Interestingly enough, planting grass in very late fall/early winter (mid-late November) can have excellent results however you will not have actual growth until the soil warms in spring.
One last misunderstood fall gardening activity is fertilization. Lawns are heavy feeders and require regular feeding throughout the fall but trees, shrubs and perennials fertilized in fall can unnaturally push growth that will not have time to harden up before winter arrives. Discontinue fertilizing in fall (September and October) until after Thanksgiving when plants are completely dormant, top growth has stopped but root systems continue to develop. Late November may be the most beneficial time to build root systems of trees and shrubs here in northeastern Ohio.
Last, but not least, I would be remiss if I did not mention spring flowering bulbs in a fall gardening discussion. Here again I find more and more confusion (understandably) with the whole fall bulbs/spring flower thing. Far too many new gardeners are shopping for Tulips and Daffodils in spring when fall is the time to plant. These spring flowering bulbs can be planted any time in fall but the sooner it is done the more likely you will not find yourself planting bulbs in the middle of a snow storm! (Yes, I have done this many times!)
So while it may not yet be fall on the calendar, as far as the garden goes we are in the thick of the season! We have had an excellent growing season so far but the clock is winding down on the gardening year so now is the time to get that outdoor planting project underway.
Now go outside and have fun in the dirt!