|
.
|
Plant of the Week
Sarvis, Service Berry,
Juneberry, Shadbush
Latin: Amelanchier arborea
As gardeners we know when spring arrives. We mark the arrival of spring by
the blooming of daffodils, forsythia, Bradford pear and saucer magnolia. All of
these plants are visitors to our gardens from Europe and Asia. Are these
foreigners to be trusted to decide when winter has passed away and another
gardening season commenced?
Over my 26 years in the Ozarks I have logged blooming dates -- all be it on an
on and off basis -- of some of the common landscape plants. The arrival of
spring this year in northwest Arkansas is two to three weeks earlier than
normal, with surprisingly little difference in bloom date between the northern
part of the state and the central part of the state, which usually blooms about
10 to 14 days before the north. This year there is maybe a three to four day
difference. These bloom dates are based on the landscape plants mentioned above,
but one of our natives, the sarvis, is not so sure spring has arrived.
Sarvis is a 25-foot tall deciduous tree that produces an abundance of five-petaled
white blooms in terminal clusters. It occurs as a scattered tree in the woods as
an understory plant, often in higher, better drained sites than where dogwood or
redbud would grow. Over my years of observation I have found sarvis to be one of
the most erratic plants with regard to bloom date, but one of the most reliable
predictors of the arrival of spring. And so far this year, sarvis is yet to
bloom.
Spring blooming woody plants develop flower buds in the fall, but these flowers
are dormant and must undergo chilling to break dormancy. Orchardists, primarily
working with apples and peaches, have developed models to determine when
particular fruit cultivars will bloom based on the concept of accumulation of
"chill hours." The optimum temperature for accumulating chill hours to break
flower bud dormancy lies between 35 degrees and 45 degrees. When the temperature
falls below freezing or above 55 degrees, no chill hours are accumulated.
For temperatures that are less than optimum but below 55 degrees and above
freezing, hours accumulate at half the rate of the optimum range. Once the chill
hours have been accumulated, blooming will commence provided the weather is warm
enough for flower buds to grow.
Forsythia requires about 800 hours of chilling to break flower bud dormancy
while Bradford pear requires about 900 hours. Sarvis requires about 1,000 chill
hours, and if it has received that amount of chilling, blooms appear very
quickly. But if it hasn’t had enough chilling it will still flower but the
flowers are slow to appear. In the typical winters of two decades ago, sarvis
was the first to bloom, often appearing in late February or early March. It
seemed to miss late spring freezes every year. In the past three winters it has
been blooming in late March and still is missing the late spring freezes. So, if
you are impatient to plant the tomatoes, you best believe the lesson taught by
sarvis, and delay another week or two.
Sarvis is an excellent landscape tree suitable for locations where a small
specimen tree is needed. It will bloom in some shade, so is a good choice for
those with tree-covered lots. Once established, plants have good drought
tolerance. Plants are available from the state’s traditional nurseries that
carry a diverse line of trees, but are not common in the mass market garden
center stores. They are not susceptible to any serious insect or disease pests,
but poor drainage can cause plant loss.
By: Gerald Klingaman, retired
Extension Horticulturist
- Ornamentals
Extension News -
March 14, 2000
Back to Archives I - L
Back to Archives Q - T
|
