Tulip query

Rodger Whitlock totototo@pacificcoast.net
Fri, 03 Sep 2004 03:30:46 PDT
On 31 Aug 04 at 0:32, Mark Smyth wrote:

> I have been repotting bulbs recently and tonight was the turn of the
> species Tulips. I know that they make a new bulb each year but most
> of mine are now divided into two or three bulbs. Any ideas why they
> would have done this? Will they bloom next spring? They are grown in
> clay pots in a mixture of bought top soil grit and a slow release
> fertilizer.

Iris danfordiae is notorious for splitting into dozens of tiny
bulblets that take years to reach flowering size -- unless it is
planted very deeply in the soil. Your species tulips are behaving
somewhat the same way.

My guess is that these bulbs dig themselves very deeply into the
soil in their natural habitat, so that there are mechanisms which
say in effect, "Hey, I'm close to the surface, time to split up and
multiply vegetatively instead of by seed." Soil temperatures or
diurnal or seasonal fluctuation in temperature may be the
determining factor.

This isn't quite right, though. The usual commercial clone of I. 
danfordiae is a sterile triploid, and such bulbs often have the habit 
of multiplying vegetatively and flowering very little.

In general, commercial clones of bulbs have been selected *because*
they multiply well as bulbs; that is, because they split up freely.

As for cultivation, try planting your tulips in very deep pots and 
then plunging these to the rim in soil or sand in a sunny position.

Even better, build a raised bed for them and plant them out. Many 
bulbs are quite unhappy in pots; plant them out where have free 
root-run, and they're like children let out of school, happy and 

A bed raised 30-40cm (12-16 inches) above grade suffices.

Given the damp Irish climate, you may want to devise a rain cover 
to keep it dry in summer.

Rodger Whitlock
Victoria, British Columbia, Canada
Maritime Zone 8, a cool Mediterranean climate

on beautiful Vancouver Island

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