Gardening Notes For December

The hustle and bustle of the Holiday Season is finally upon us!  December is off to a seasonally cool start and fortunately, we received a few inches of rainfall in late November that will help the plants through the winter freeze.  This is the time of year to properly prepare the garden for winter as autumn bids farewell and the sub-freezing temperatures of winter are just around the corner.  As time permits between the cooking and the shopping, continue your notes and ledgers.   Happy Holidays to all!

Things to do:

  • Finish removing leaves from lawn areas.  If possible, shred the leaves with the lawn mower and add them to perennial or annual beds as mulch.  The shredded leaves that remain in the turf are actually very beneficial for the turf.
  • If you have water features or ponds, keep the leaf nets over the pond at least through months’ end to keep out any leaves that are still blowing about.
  • Decorate those containers or window boxes remaining outdoors for the winter.  Evergreen boughs such as Yew, Pine, Hemlock, Southern Magnolia, fruited Holly or Cherry Laurel can be pruned from the garden. For large pots, add containers of red stemmed Dogwoods or Willow for their glowing red stems.  Add some white painted birch stems, which many Garden Centers carry, and an attractive winter container will result!
  • If you have recently planted an evergreen, make certain that the soil remains moist in case we have several weeks without another rainfall.  A 3-4” layer of mulch over the roots certainly helps to retain the moisture. 
  • Rhododendrons, Holly and other broadleaf evergreen shrubs that have been planted this fall will benefit from an application of an anti-desiccant spray.   Apply during periods when the temperatures are above freezing for several hours.
  • Finish cutting back those perennials which have little winter interest.  Stems and fallen leaves often serve as a camouflage for mice to hide beneath and eat the crowns and tubers of various perennials, along with the bark of trees and shrubs.
  • Finish digging up Canna and Banana tubers, letting the soil dry so it can be knocked off and then wrapped and stored in a cool basement.
  • Finish gathering seed from various annuals that are not cultivars and which will come true from seed.  Dry and place in labeled packets for sowing come spring!
  • Remove the old foliage from Bearded Iris, since the borer egg masses overwinter on the previous year’s foliage. 
  • Consider edging bedlines if the ground is not frozen and time avails, as it will be one less item to consider come the spring!
  • Pot-up daffodils, tulips or minor bulbs into shallow pots and place them in the back of an unheated garage for the winter.  Water when the soil appears dry.  As the shoots begin to appear in February, place them in a sunny but cool window (hopefully in the garage).  They will provide nice early color to the kitchen table in March or for outdoor containers in March, April and May.
  • For Tea Roses, mulch the graft union with soil, leaves or shredded bark after the soil has started to freeze.  This will ensure that the named selection that has been budded onto a rootstock will not perish during the winter.  It is often beneficial to partially prune Tea Roses back to reduce any potential wobbling due to winter winds. Complete the pruning come spring.
  • Winterize lawn mowers and other gas-powered equipment.   This entails cleaning or replacing the filters and amending the fuel with an additive that will prevent it from becoming more viscous and potentially blocking fuel lines come spring.
  • If there is access to composted or even fresh horse or cow manure, it can be spread now in the annual beds (not vegetable or perennial).  Shredded leaves can be spread as mulch to vegetable gardens if there was not sufficient time to sow a cover crop.
  • Evaluate the Garden to see if it is in need of December flowering or fruiting cheer!  Plants like Mahonia x ‘Charity’ and Aster carolinianus are presently in full bloom and Ilex verticillata is full of glorious fruit!