By Trey Pitsenberger, co-owner
Besides trees and shrubs, plants can be divided into
three types- annuals, biennials and perennials. Annuals
grow from seed to flowering size and then die in the
course of one year. Annuals are important for keeping
our yards colorful throughout the summer or winter months.
Marigolds, Zinnias, and Pansies are well known annuals.
Biennials, such as foxglove and hollyhocks, usually take
two years to complete their lifecycle. They grow the
green leafy portion in the first year, and flower in
Perennials can be divided into two camps. Short-lived
perennials last for about four years, but can be kept
longer by dividing them every year. Long-lived perennials
can sometimes outlive the gardener that planted them.
While technically trees and shrubs are perennials, the
perennials we are discussing are called herbaceous. Herbaceous
means the plants have soft, non-woody stems. There growth
above ground dies out each winter, while the roots remain
alive to send up new growth each spring. Here in the
foothills our winters are mild enough that sometimes
the growth does not disappear completely.
The reason that fall means perennials is that now is
the time to plant, as well as divide these plants. Now
that the weather has cooled is when the least amount
of stress is put on these plants as you dig them from
the ground or pull them out of their containers to plant
in the ground. The soil is warm from a long summer and
this will encourage root growth for the next month or
so. You may not get lots of top growth now, but the larger
root system of fall planted perennials will mean rapid,
lush growth come next spring.
Most all perennials can be divided but a few should
be left alone. Monkshood (Aconitum), most euphorbias,
gypsophila, Christmas-rose (Helleborus), and oriental
poppy (Papaver orientale) should never need to be divided.
Generally if a plant is flowering and growing well division
is not necessary. Sooner or later your perennial may
stop flowering well, or out grow the area they inhabit.
This is when you should divide.
Perennials that make strong, dense clumps can be divided
by lifting the clump from the ground with a shovel or
digging fork. Cut into the clump with the shovel or use
to digging forks back to back in the center of the clump
and pry them apart. If the foliage has died you can cut
it back making it easier to reach the roots. If the plant
has woody roots you may have to dig the clump from the
ground and using a sharp knife sever it into sections,
each with some roots and a growing bud or shoot. Plant
these sections as you would perennials brought home from
the garden center in cans. Dig the hole three times the
width of the root mass, but only as deep. Mix organic
matter with the soil, such as fir mulch, planting mix,
or compost. Add a pre-plant fertilizer like Master Start.
Don’t bury the plant any deeper than it grew in
the ground or can. Water well after planting and until
the rains arrive.
Yarrow, anemone, agapanthus, campanula, chrysanthemum,
coreopsis, gaura, daylilies, iris, shasta daisy, veronica,
salvia, and rudbeckia, are just some of the perennials
that can be planted or divided now through late fall.
Try to finish before the ground gets cold and the wonderful
benefits of fall planting diminish. Come spring you will
be amazed at how quickly the plants grow and flower compared
to one planted in spring.