* Since the container raises the plant above ground there isn't any soil blanket to insulate the roots of the plant. It is therefore recommended that plants placed in containers be two zones lower in cold hardiness than the hardiness zone they are to be grown in. Coastal Connecticut is zone 6, so use plants in your containers that are hardy to zone 4. Examples of plants we recommend for containers in the winter are Colorado Blue Spruce, Alberta Spruce, Weeping Norway Spruce, Umbrella Pine, Siberian Cypress, Arborvitae and Juniper.
* You should use containers that have a drainage hole(s) in the bottom.
* Professionals no longer line the bottom of the container with gravel. This is considered passé. Use a coffee filter to cover the hole(s).
* To help compensate for the moisture stress factor McArdle's recommends 'Soil Moist'. These granules absorb irrigation water and gradually release it, as it is needed by the plant. McArdle's also prescribes 'Wilt Pruf', an anti-desiccant spray for evergreens.
* As winter sets in and the potting medium freezes, you must cease watering. water only in winter when soil is unfrozen and approaching dryness.
* If the paving area where the planter is to be placed is of a blue stone or brick, consider utilizing 'Pot Feet'. These are either terra cotta or cast stone. They are useful as they elevate the planter above the pavement surface, allowing it to dry out. This will eliminate or lessen the severity of staining pavement surfaces, from draining irrigation water. ·
* Be advised that the larger the container, the greater insulation of the potting soil around the plants' roots. This increases your chances of success and removes stress from the plants' roots.
McArdle's does not recommend and will not entertain potting Boxwood (Buxus), Holly (Ilex) or any of its relatives in containers. Boxwood and Holly have traditionally been planted in containers in both England and Virginia (and South). These regions are in plant hardiness zones 7 and 8. Our New England climate is not amenable to the culture of Boxwoods or Hollies in containers.