University of Vermont Extension
Department of Plant and Soil Science
Spring News
Article
SPRING BULBS AFTER
BLOOM
Dr. Leonard Perry, Extension Professor
University of Vermont
Once spring flowering bulbs finish
bloom, proper handling and care of perennial ones will help them to bloom again
next year. The first question to answer
is, which of your bulbs are perennial?
This may be difficult with some tulips, most of which are treated as
annuals.
Chances are, if your bulbs grew and
bloomed this spring, they are hardy in your area. If they should have been hardy but didn’t
come up or bloom, there could be several reasons. If the soil is too wet (bulbs like good
drainage), they could have rotted.
Something could have eaten them, above or below ground. Perhaps they started growing last fall, or
early in the spring, only to have the buds killed by cold.
A couple rules apply to all bulbs in
addition to providing them with good soil drainage. When planting, hopefully you added some bulb
fertilizer or source of phosphorus (for healthy roots). Before, and during, bloom or both are good
times to apply more bulb fertilizer.
This can be a granular form as bulbs are emerging. Or, you can water with a liquid
fertilizer. The key is to provide
nutrients then as the leaves are making food for next year.
The second rule is to let the leaves
die back naturally. If they are
unsightly and fall over, try clipping tips back by a third to a half. Daffodil leaves, if not too many bulbs, can
be bent over and tied in a knot or with a rubber band. If you have room, plant some annual flowers
in front or in between to hide the dying bulb leaves. These leaves are key to producing the food,
and so healthy bulbs, for next year.
You can, and should, cut off flower
stalks after bloom, especially if they start to form seeds. You want all the bulb energy to go into next
year’s bulb, not seed production.
If you must dig up spring bulbs, either
to make room for annual flowers, or for other reasons, just make sure you leave
the leaves on. Digging and transplanting
often will make them die back faster. If
you want to place the bulbs in a temporary holding area, or “heel them in”, to
replant next fall, just make sure you mark them so you can find them come
fall! An easy way to do this is to just
“pot” the bulbs in a large pot with soil, compost, or soil-less medium where
you know exactly where they are once the leaves die off.
If bulbs are becoming too crowded, as
often happens with large daffodil clumps, or are blooming much less than in
previous years, perhaps they need dividing.
Dig and shake the soil off bulbs after bloom, leaving leaves attached if
not died off already. Bulbs should
separate naturally, otherwise plant back ones still joined together. Don’t forcibly pry bulbs apart.
Tulips are a bit different. If you’re like me, if you got 50 beautiful
tulip blooms the first year you may have gotten only five the next and none the
next, perhaps not even leaves. Most of
the tulips you find and buy and love are hybrids. Once they reach several years old, the stage
in their life in which they produce the biggest flowers and the stage we buy,
they split after bloom into many smaller bulbs.
If you’ve dug up tulips after the leaves start dying in early summer you
may have noticed this. This is their
means of multiplying naturally, and a trait of course bulb growers love and
often select them for. So these bulbs will
not generally bloom again, so treat them as annuals.
A few groups of hybrids, notably the
Darwins,
Emperors and some Triumphs, don’t split and so will come back for many
years. You’ll find these marked in
catalogs and stores as perennial or for “perennializing”. Some plant tulips deeper in fall, nine inches
or more deep instead
of the usual five or six inches, and claim this helps make them last more
years, possibly from
cooler soil temperatures.
I don’t mind treating most my tulips as
annuals, as I like to try new varieties each year and don’t have the space for
many, and they are so beautiful after a long winter that I find they are worth
it. But, if you do want to try and keep
the “non-perennial” tulips, they must have all the following.
--
If the bulbs have already split when you dig them, you will need to nurse the
baby bulbs for several years until they are large enough to bloom.
--
Tulips need a long, cool spring to generate lots of plant food, and soil rich
in nutrients.
--
Dry tulips quickly when dug, and store over summer with lots of air circulation
in warm to hot temperatures, not cool.
Keep out of direct sunlight as this can scorch the bulbs.
These conditions mimic the ones in
the tulips’ native habitats in the foothills of the Himalayan mountains, or the
steppes of eastern Turkey. I’m just glad the Dutch, with over 400 years
experience producing these bulbs and precisely controlled temperature and
humidity chambers, have figured how to copy these conditions and provide us
with such a welcome treat for spring and a new growing season.
Return to Perry's Perennial
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