Come spring, what do you do with the perennial herbs
in your garden? Check all of the woody perennials for new growth —
mainly lavender, oregano, sage, tarragon, thyme, winter savory, and (if
you’ve provided a bit extra protection in the central-Illinois
hardiness zone) rosemary. Once the fear of hard frost is over, usually by
mid-April, the time has come to prune the woody perennials that have
survived the winter outdoors.
If you have regularly harvested during the previous
growing season or pruned back dead wood last autumn, your woody
perennial herbs may not need much pruning. If your woody herbs have been in
the garden five years or longer, they may be too woody to
salvage. It’s usual to replace woody perennial herbs after five
years. Remember also that a few herbs are biennials and will produce
flowers and seeds only in the second year. In other words, don’t trim
your caraway plant that overwintered, because it will produce its seeds for
harvesting in early July.
OK, back to spring pruning. Generally prune dead and
scraggly growth on woody perennials, and clear out any debris or leaves
around the bases of all plants.
Oregano requires
pruning every spring to control plant spread. You may use a garden spade to
sever roots around the plant (and these root divisions may be planted in
another garden).
Lavender needs
all-around trimming of at least one or two inches in the spring. If
you didn’t remove flowers and dead stems in the fall, do it now,
cutting back to where new growth has started.
Rosemary should not
be trimmed until after it has flowered, after which it may be pruned
severely. In warmer climates rosemary is grown as a year-round hedge. New
rosemary plants are fairly easy to start from spring cuttings (roughly six
to eight inches long, with the cut end trimmed of leaves and placed in
sandy potting soil).
Sages require woody
branches to be pruned. Some cultivars, such as tricolor sage, may be
subject to severe die-back during the winter. Look for new growth —
even wait until end of April — and prune back to those new spring
leaves. Sages usually require spring shaping. Keeping flower buds trimmed
off helps maintain a tighter-looking shrub. Also note that clary sage, a
biennial, self-seeds after blooming in the second year.
Tarragon (use only
French tarragon as a culinary herb) requires general spring pruning for
shaping purposes. It only gets bigger and bigger every season, so consider
dividing French tarragon by its roots in the early spring every three
years, starting with “new” plants in your garden and
sharing other root divisions with friends.
Thyme needs an
early-spring pruning to remove dead woody sections, but wait until after
the plant flowers to perform general light pruning — thyme
doesn’t respond well to heavy pruning.
“Spring Wildflowers,” the latest program in the yearlong University of Illinois
Extensive “Four Seasons” telenet series, will introduce you to
the wonderful beauties found in our parks, forests, and back yards.
Identifying spring woodland wildflowers will be the
focus of this program by Jennifer Fishburn, horticulture educator and Illinois Times columnist.
Fishburn will also discuss some prairie wildflowers and offer tips on how
to incorporate wildflowers into the home landscape.
“Spring Wildflowers” is offered at 1 p.m.
Tuesday, April 19, and repeated at 7 p.m. Thursday, April 21.
In Springfield, the “Four Seasons” series
is held at the U of I Extension Building on the Illinois State Fairgrounds.
The telenet system allows live discussions between the instructors and
gardeners throughout Illinois.
Please call 217-782-4617 to reserve a seat and
information packet. Each session costs $2.
This article appears in Apr 14-20, 2005.
