PlantinG and renovation 49
Planting depth
Containerized perennials should be planted at the same depth at which they
were growing in the pot. Plants placed too high can dry out; too low and they are
more subject to collar rot. Dicentra plants, irises, and peonies have overwintering
buds that sit on or near the soil surface; if planted too deeply, these perennials
not only might not flower, they can also rot. Particular care must be taken with
peonies not to plant with buds more than 2 in. below the soil in cooler climates
(see discussion of Paeonia hybrids in the Encyclopedia of Perennials for more
details). Bare root plants ideally should be soaked in a bucket of warm water for
30 to 60 minutes prior to planting. Also, any dry containerized perennials should
be watered before planting.Further notes on planting
The soil between newly planted perennials should be
leveled before mulching. A small shrub rake is most
eff ective for this. I leave only a single plant label per
group of plants in the ground, which keeps the new
planting from looking like a mouse cemetery with
little white labels sticking up from the ground. In
addition, the labels will not be pulled out by the rake
and will not pop out with fluctuating temperatures. I
also leave a label next to each very small plant, such
as late-emerging platycodons, eutrochiums, or
asclepias, so that these plants do not get covered
with mulch.
I prefer to use a trowel for most planting,
although with the 1-gallon and larger perennials,
transplant spades (sometimes called poacher spades)
are a hot commodity. These are narrow, lightweight
small spades (weighing only about 4 lb. and measur-
ing 39 1/2 in. long). They are great for larger-size
plants, and some of my crew like to use them for
quart-size plants as well. If any plants are root-bound,
I make 3 cuts in the root ball with hand pruners
before planting, to promote adventitious roots that
branch into the newly prepared soil. (Adventitious roots originate from a stem or
other part of the plant where roots do not normally occur.)
Plants can be firmed into the soil by pressing on them with your hands; larger
grasses and perennials can be firmed in with your foot. Again, nothing dramatic
is needed here, and be careful that a well-meaning crew member isn’t stomping
the perennials to death.
If a plant looks like it has become leggy in the container, cut it back by a third
to half at planting to help create a fuller, healthier plant. Artemisia absinthium
‘Lambrook Silver’, for one, often needs this treatment.
When planting new perennials into an existing garden where the entire bed
has not been prepared, be sure to dig a suffi cient-sized hole, at least 2 times the
size of the root ball. This helps prevent the plant’s roots from growing into soil
that has not been properly prepared while the new plant is establishing. Incorpo-
rate organic matter into the hole and the backfill during planting.
Amateur and professional gardeners alike have a tendency to accumulate
used plastic pots and flats at an overwhelming rate. In many areas, pots can be
recycled, and many nurseries accept used pots as well. I recycle my pots, and I
urge you to do the same rather than throwing them out.
If a containerized plant is root
bound, make 3 cuts into the root
ball to help promote branching
of the roots into the newly
prepared soil.