|February is a good time to fertilize trees,
shrubs and evergreens, says Dr. Susan Hamilton. . .
UT Gardens' Plant of the Month:
means "dew of the sea." It’s an appropriate name for this
traditional garden herb that is native to the arid coastline
of the Mediterranean. There it is watered by ocean mists.
(Rosmarinus officinalis) is a tender shrub. Its glossy,
strongly scented, evergreen leaves are needle-like with a
flashy light stripe underneth. Most rosemary cultivars have an
upright form and can grow up to 6 feet tall. Prostrate forms
creep along the ground. Depending upon the cultivar, flowers
can be either blue, lavender, pink, or white. Various
cultivars bloom at different times of the year.
selections of rosemary are cold hardy only to zone 8, but five
cultivars are known to be hardy to winter temperatures common
in Tennessee (zone 6 or 7, depending on your location in the
landscape uses add to rosemary’s popularity. It can be clipped
into an impressive herbal hedge or shaped into a fancy
topiary. Bonsai forms will work well for those who have enough
patience. Rosemary also can be a focal point in a mixed
is a must in a fragrance garden, and it's the cornerstone of a
drought-tolerant garden. The prostrate forms look bountiful in
containers and hanging baskets, and they create an impressive
evergreen ground cover as well.
you grow a cold-hardy selection, rosemary must spend the
winter indoors. Even indoors, good air circulation is required
for survival. If you try a cold-hardy selection, I recommend
these upright cultivars: ‘Salem’, ‘Hill Hardy’, ‘Arp’, and
‘Athen’s Blue Spires’. ‘Dancing Waters’ is an impressive
cold-hardy creeping selection. All of these cultivars are on
display in the UT Gardens. (For more information, visit the
Gardens at http://utgardens.tennessee.edu.)
prefers a well-drained soil with a pH range of 5 to 8. It
performs best in full sun but can tolerate partial shade. Most
selections do well when planted 2 to 3 feet apart. During the
growing season, pinch back growth tips 2 or 3 inches to
promote bushy plants. Cut them back hard only in the early
spring to allow new growth time to mature. Plants can be
pruned lightly throughout the growing season to control shape.
Non-cold-hardy cultivars should be grown in pots where
they can be brought indoors during winter. Be sure to place
them in a sunny window or under artificial lights. Use
well-drained potting mix, and be careful you don't over water
them. Soggy soil induces root rot diseases.
is not a heavy feeder. For plants grown in the ground year
round, fertilize every spring with a well-balanced fertilizer
labeled for perennials. For those grown in containers indoors,
fertilize them just during the growing season with either a
slow-release or water-soluble fertilizer. Be sure to follow
start new rosemary plants by air-layering or from stem
cuttings. Rosemary will grow from seed. The process is slow,
however, and the seedlings are not true to cultivar. Plants
can be set out in the spring when the weather has warmed.
(Cold-hardy types can also be set out in the fall.)
the garden, rosemary has numerous uses. It has a strong flavor
and can be used dried or fresh (snip or mince finely) in a
bouquet garni with chicken, meat, vegetable, and tomato
dishes. Remove the leathery sprigs before serving. As a leaf
tea, rosemary can be soothing to an upset stomach.
rosemary is popular in sachets.
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Dr. Susan Hamilton is an associate
professor of ornamental horticulture in the University of
Tennessee Department of
Plant Sciences and director of the UT Gardens. The UT
Gardens are located on Neyland Drive in
Knoxville. They are open seven days a week during daylight