Gardening Notes For September

September marks the start of getting the garden – and the gardener – ready for a long winters rest.   To this end, consider how best to overwinter and to make room for your favorite non-hardy plants indoors, as well as considerations for your outdoor hardy plants.  However, we still have several months remaining for plants to grow, so keep your focus on watering – August has been rather dry.  For trees and shrubs, any plant that has been installed over the past few years will be stressed by the current dry conditions.  In addition to watering, take good notes and pictures on your use of perennials and annuals since after the first frost these pictures will be all that remains of this year’s favorite combinations!

Things to do:

  • Continue to keep your lawn mower blades set high if you need to cut the lawn, as this will minimize the stress to the turf. 
  • September is a great time for the re seeding of bare spots, or for the installation of sod, since the upcoming cooler temperatures, heavy dews and more consistent rainfalls combined with warm soil temperatures promotes good root growth and turf establishment.
  • September is a good time to aerate those portions of the lawn that receive excessive foot traffic or have otherwise developed compacted soils.
  • If you have yet to start, take cuttings of your favorite annuals that you wish to overwinter.  It is far easier to over-winter a small plant that should be free of most insect and disease rather than lifting a large plant from outdoors and bringing it inside.  Also, harvest and clean the seed from those annuals and vegetables that come true from seed.  Remove them from the ‘seed head’, store them in small paper pouches that are properly labeled and place them in the refrigerator (not the freezer) until next spring.
  • Remove those annuals that look excessively tired or leggy and keep removing annual weeds such as crabgrass.  Remember, on average a seed lasts for seven years and one plant going to seed equates to seven years of work!
  • Send in your bulb orders!  October is a great month for planting bulbs.  For Colchicum (Autumn Crocus) and other autumn bloomers such as Crocus speciosus, get in your orders in early September, since they bloom in late September and early October.
  • Inspect and evaluate your ornamental small trees, shade trees and shrubs.  The lack of rain over the last few weeks of August will highlight those plants that are stressed.  The leaves will often droop, or begin to develop fall color.  This could indicate insect or borer problems, internal decay, root damage, or disease issues. 
  • September is an ideal time to add woody and herbaceous plants to the garden.  The soil is warm and although it is often a relatively dry month, the cooler days and moister weather ahead will allow the plants to establish an adequate root system before next summers heat and drought.  Woody plants that are not fall transplant hazards can be transplanted, and those that are fall hazards can be planted if they were dug the previous spring or are grown in containers.
  • For the vegetable garden, continue to remove plants that are no longer producing. Plant leafy crops that mature in 40-50 days and appreciate the cooler nighttime temperatures, such as Arugula, Spinach, Bok Choi, Kale and Lettuce.
  • Consider the installation of low houses or tunnels, which are essentially small greenhouses that are placed over a row of cool season vegetables.  It enables the gardener to harvest well into December, or for crops such as spinach, lettuce and kale, all winter!
  • September is an opportune time to plant garlic too!  ‘Music’ is an old fashioned and good performer, but try some of the many other selections that are on the market too!  Plant in a location that will be in full sun through next August, which is the harvest period.
  • If you live with large deer populations, put wire cages around recently planted trees to avoid the bark being rubbed and damaged by bucks.  Damage to bark is far more harmful than the nibbling of a few leaves.