Expert: Long Island Gardener - 8/30/2006

Question
I live in zone 7. When can I cut back the tops of the flower that has finished blooming?

Answer
If you are going to save your glads and pull them up for next year, you should have already cut the spent flowers -- NOT the foliage -- to keep your gladiolus flowers from producing seeds.  All flower energy should be saved for next year's flowers.  You simply cut the stem at the point where it meets the leaves.

But DO NOT cut the leaves back, if that is what you mean by "tops of the flower" - sorry, I am not sure what you mean by "tops".  Don't cut any leaves off.

The most important thing about cutting your glads is not the timing - the "when".  It's the "where" - where are you going to cut the flower stalk, and how much foliage are you going to leave on the flower to generate flowers for next year?

But leaves with gladiolas, like leaves for tulips and daffodils and other spring flowers, and like leaves for lilies, are needed to produce the food for next summer's flowers.  The more leaf are you remove, the more you weaken the plant's energy for flower production.

Got that?

University of Nebraska posts a "Fall Care" page for Gladiolas (hortparadise.unl.edu/Newsrelease/News/GladiolaFallCare.htm) that applies to anyone who wants to keep these pretty corms year after year. They explain the autumn procedures for gladiolas very nicely: "If the tops are still healthy leave the corms in the ground until the foliage begins to die back, or until just before a hard freeze. This give the plants the longest time possible for the corms to grow and increase in size, resulting in bigger flower stalks the following year."

They point out that lifting the gladiolus corms is the right thing to do - if the leaves look like they are withering.

"If the foliage does begin to die back dig the corms as soon as possible to prevent disease problems while the corms are in the ground."

You can always try to keep these in the ground, Cindy.  Planted deep enough, in the right place, Gladiolas often survive a Zone 7 winter.  I was as surprised as you to see this.  But this is what I do each year.  If I didn't keep finding new glads I like even more, I would not have to plant a gladiolus.

Besides, I go through enough tending to the Dahlias every fall.

So... if you want to cut the tops of your Gladiolus bulbs, and keep them in the ground, wait until they are turning brown, then snip!  And mulch.

Good luck - Any more questions, I'm still here.