Pulsatilla

[David Nicholson]

I've a few seedpots of Pulsatilla species I sowed late end of the Summer that have good germination. Given that they form tap roots should I prick them out as soon as they are big enough to handle or should I leave them in their seed pots until Spring? Any info welcomed.

[Maggi Young]

Unless they are very congested, David, I'd leave them alone right now. They shouldn't grow much more now anyway so there shouldn't be  a huge problem in getting them apart next year. If they are getting overcrowded in  their seedpot  then a transfer of the whole potful to a bigger pot to allow them at least more root room would be possible.
Tap rooted or not, I'm not a fan of pricking out baby plants of any kind at this time of year - even supposing I could see 'em through the  rain and gloom!

[David Nicholson]

Cheers Maggi, just the info I needed.

[Maggi Young]

I sometimes feel a real wimp  when I read of those folks who prick out every seedling of every plant as soon as the seedlings are "big enough to handle" - and I accept that at some times of year that might be the course  to take - but experience- usually bitter experience- tells me that it is far safer to wait !

[johnstephen29]

Hi Maggi I useally leave my cyclamen seedlings in the seed pot till they are at least two years old and the same amount of growth. I then let them die down in there second year and then repot individually into there own pot.

P.s. Sorry for the trouble I caused you with the Galanthus question, didn't think it would get so heated.

[Maggi Young]

Sounds like a good system with the cyclamen - get stronger plants that way, don't you?

(No need to  apologise - nothing there your fault! 

[johnstephen29]

Cheers maggi, yes you do 

[penstemon]

One of the problems with pricking out seedlings of taprooted plants is that the fine root hairs can attach themselves to the sides of the pot, and when the root is disturbed, the root hairs are detached, and that's that. Particularly true of American astragalus and oxytropis.
There was some talk, years ago, that some plants are monocarpic unless sown in situ (Physoplexis comosa in particular). While I haven't found this to be true, it does point to the sensitivity of some plant roots, particularly taprooted plants, and the need for the plant to get its root "right" in order to survive for a long time.
If you can't bear not transplanting the seedlings, one way to do it is to float them out. Soak the pot in water, jiggling it a little, until the seedlings just float out, and then re-plant them.
I once germinated seeds of a pulsatilla labeled "sp., Death Lake". The name was so evocative. Turned out there was a reason why the plants were so named....

[Gene Mirro]

David, if you are going to leave them outdoors to go dormant, I would not disturb the roots.  I have a theory that plants don't heal themselves very well when they are dormant. 

If you are growing them under lights indoors, then I would definitely transplant them when they have two true leaves.  Just make sure that you don't leave the roots exposed to the air for more than a few seconds.  Put them on the potting bench and cover immediately with moist potting mix until you plant them.  Give them a little liquid fertilizer every few weeks.  They will grow like weeds.  You might even get some blooms next summer.

I don't have any problem transplanting perennials with tap roots, as long as they are not too big.  If you wait too long, the roots will get hopelessly tangled at the bottom of the pot, and your chances of success will be poor.  One way to avoid this is to sow the seeds in a very tall pot or band.  However, I do not transplant any kind of bulbous plant individually.  I always transplant the entire contents of a pot as a block.  This does not hurt them at all.

Bob, I have grown many batches of Physoplexis and transplanted all of them.  I can confirm that they are not monocarpic when this is done.  All of these horror stories about Physoplexis are really odd.  Yes, they are difficult to germinate unless you use GA-3.  But once they are up, they aren't bad.  I think people should grow them like Campanulas.  Don't starve them.  And you must kill your slugs.

[mark smyth]

I have two large pots of Pulsatilla that need potting on next year. Do I do it when new leaves start or before?

[Gene Mirro]

Mark, I assume you are talking about flowering-size plants that are dormant now, right?  I always transplant mature plants in early Spring as they start growing.  They seem very forgiving of disturbance then.But whether it's a seedling or a mature plant, you should get the roots back underground as soon as possible.

[penstemon]

Bob, I have grown many batches of Physoplexis and transplanted all of them.  I can confirm that they are not monocarpic when this is done.  All of these horror stories about Physoplexis are really odd.  Yes, they are difficult to germinate unless you use GA-3.  But once they are up, they aren't bad.  I think people should grow them like Campanulas.  Don't starve them.  And you must kill your slugs.

Slugs?
I had a trough full of Physoplexis, mostly self-sown, until last winter. Sigh.

[Gene Mirro]

Slugs?
I had a trough full of Physoplexis, mostly self-sown, until last winter. Sigh.

In your climate, a trough might freeze and thaw very quickly, especially with the sun and wind.  That may have killed the roots.  Or maybe your soil mix got too dry.  I once lost thousands of containerized plants after a fast freeze from 50F down to 10F.  Even very hardy plants need to freeze and thaw very slowly.  That's what happens in the garden.  What would happen if you threw a potted plant into the freezer, and then took it out and thawed it on your kitchen counter?  It would be dead, I promise you.  Soil in the garden freezes and thaws very slowly, especially if it's mulched.  My plants in the ground have survived several big freezes down to 10F, which occurred after a very mild Fall.  They were OK.

I think what is happening is that rock gardeners are providing very specialized habitats for plants like this, like troughs or tufa.  But those habitats actually increase the stress and the chance of plant loss.  They are too cold in Winter and too hot in Summer, and too dry always.  And the plants are starved.  I don't think Physoplexis are tough enough for that.  Try growing them in a well-drained bed of sandy loam in the garden.  Feed them with dolomite lime and a little NPK fertilizer.  Don't let them dry out while they are in active growth.  Give them a little shade during the hottest part of the day.

[penstemon]

What happened was that there was a layer of water on top of the otherwise frozen trough for several weeks. The plants had been in the trough for twenty-odd years and had never experienced this. When they did, they died. I'm sorry to report that this also included the white form of P. comosa.
Frozen solid is the best way to go. In most winters the soilless mix is frozen for three straight months. Like now.

I did see a slug here, once.