Daffodils know what they're doing
By JON FRANKLIN,
Staff Writer
The daffodils
have raised their
delicate yellow
heads in defiance of
winter, flowering as
much as four weeks
earlier than they
were supposed to.
But don't fear for
the daffodil. It is a
lot hardier than it
looks.
Besides, jumping
the gun is its basic
evolutionary
schtick.
Daffodils -- or
jonquils, as they are
often called locally
-- store energy and nutrients in one season so
that they can pop up late in the
following winter. That allows them to flower and
soak up the rays of the
strengthening sun before more conventional plants
can get their metabolic acts
together.
If that puts them at risk, a plant
physiologist at N.C. State University says
the most they have to lose is their flowering
heads -- their unopened flowers and
leaves are frost-proof.
In any event, August deHertogh suspects that
the bulbs guessed right in this
case, and that their early appearance will almost
surely pay off for them in terms
of bigger, healthier bulbs for the spring of
2000.
DeHertogh says the daffodils are going into
this season in especially good
shape, because 1998 was a good year for bulb
development. The spring was
relatively cool, and the cold snap in December
was long enough to set the bulbs'
biochemical growth triggers. As a result, the
bulbs blooming now are flashier
than usual.
To add to the spectacle, the unusually balmy
nature of early February caused
early-, mid- and late-season bulbs to bloom at
the same time.
As a harbinger of spring, the daffodil is
first in line at the botanical banquet
that is the growing season. It sprouts, flowers
and makes new bulbs before
overarching trees and bushes can produce their
shading leaves. By the time the
weather warms and taller plants shade the ground,
the daffodil already has
satisfied its energy needs. Its foliage turns
yellow and disappears.
But while the plant may disappear during the
summer, deHertogh says, it
doesn't go dormant. Instead it retreats inside
its own bulbous world and, using
the energy it stored in the spring, slowly
develops through the summer.
Embryonic leaves and flowers appear inside. By
December it has sprouted,
made new roots and sent new leaves to the
surface.
Then it stops, waiting for cold weather.
There are many varieties of daffodil,
deHertogh says, and they have a wide
range of chill requirements. Some tropical types
require none and will be killed
by freezes. But most require a period of chill
that ranges from weeks to months.
The cold destroys a biochemical that retards
growth and, once that is gone, the
bulb is ready to explode out of the earth in just
a few days. All it needs is a little
warmth.
"Daffodil bulbs are biocomputers," deHertogh
says. "They can detect
temperature changes of five degrees centigrade
and react in about
two-and-a-half days."
The slow reaction time keeps them from
sprouting after just one or two
warm days in midwinter, but when there's an
especially warm period, as there
was this year, they are in a position to react.
If they mis-guess, and the warm spell is
followed by freezes, there is usually
little damage done.
"We don't worry much about small drops in
temperature," deHertogh says.
"If a night goes down to 30 degrees, or even into
the upper 20s, it doesn't hurt
them one bit." The foliage and unopened buds can
even withstand temperatures
in the teens.
Opened flowers can be another matter. They
are more fragile than the rest
of the plant, and as the temperature drops near
20 they can be damaged. The
longer the flower has been opened, the more
susceptible it is. Still, he says, the
weekend's cold snap didn't damage the flowering
daffodils at the university's
arboretum.
"Even so," he says, "if somebody has a nice
bed of daffodils and they've
been in full flower for a couple of days and the
weatherman says that we're
going to go down to 15 degrees or 20 degrees,
well, they might want to cut the
flowers and bring them in to enjoy inside. But
only cut the flowers. Leave the
foliage. That's the key."
DeHertogh says daffodils are often
misunderstood even by expert gardeners.
For many, for example, it seems counterintuitive
that this year's flower was
made last year -- and the leaves that remain
after flowering seem superfluous
and unsightly. So they mow them off. Even those
who understand that the
leaves must stay may bundle them up and, in the
process, make it impossible for
photosynthesis to take place. And, deHertogh
sighs, there is an apparently
unkillable myth that daffodils should be
fertilized immediately after flowering.
"Fertilize in the fall," he says. "As soon
as they flower they quit taking up
fertilizer. They start recycling things within
the bulb. In this neck of the woods,
November is the best time to fertilize them. If
you fertilize them after they've
come up, or flowered, the fertilizer won't get
down to them even if they could
use it then. What's more, you can actually hurt
them. The major disease of
daffodils is fusarium, basal rot, and too much
nitrogen helps create the potential
for the disease."
After the flower, the leaves gather sunlight
to make the chemical energy it
will use during its out-of-sight underground
phase. Photosynthesis stops, and
the leaves turn yellow, when it gets hot in June.
Until then the leaves should be
allowed to spread out and sop up as much energy
as they can.
"Don't cut the foliage off; don't tie it up
in beautiful ribbons, because the
photosynthesis is very important between
flowering and leaf yellowing."
Which is another reason, of course, why it
is in the daffodil's best interests
to bloom as soon as possible. The earlier it
blooms, the longer it will have to
gather energy before summer sends it underground.
The message is: Don't fear for the delicate
daffodil. It isn't so delicate.
"The odds are," says deHertogh, "that they
are better off for flowering a
month early this year. It gives them an extra
month of photosynthesis. In fact, I
can predict already that next year will be a good
year for daffodils."
