Root growth: really mostly in summer?

[plantswoman]

Hello there,
I have heard/read several times on some forums that Hostas do most of their root growth around June-August (depending upon the climate zone they are in) as they are a kind of "warm region plants". I was wondering whether you could confirm this or even point me to some reliable author/ paper to confirm this. And would this be before flowering (as a rule)? My own experience with hostas is just far too limited, getting my first plants in 2007 and paying them proper attention since last year. It does make sense and I got a similar hint from a nursery guy who divided his Pennisetum grasses around June when they startet to grow new roots.

Well, thanks for your oppinions or some information,

yours, Anna

[Tigger]

Check out the "To Divide..." articlefrom Bob Solberg. His experience is that hostas grow new roots after each flush of leaves hardens off. For many hostas, you get only one flush of leaves in the spring, but many hostas will put out a second (or even third) flush later in the year, followed by a period of root growth.

Welcome to hostadom!

[Chris_W]

Hi Anna,

I can confirm this, though many years ago when I was first starting I didn't realize this either. Hostas are warm season growers (not necessarily warm region). They put out root growth after the soil warms and only grow roots during that time (given the proper conditions of water and aeration). First they put out a flush of leaves in the spring, then they grow roots, and the roots don't grow over the winter time. In the fall and early spring they form dormant buds under the soil (which is why it is important that the crowns should be covered up).

Trust me on this - I dig hostas continuously almost year long (from March into December) so I get to see them at all stages of growth. The new roots don't start coming out from the crown until after the first flush of leaves have formed. Here in Michigan that is typically in June, though this year we were really early and new roots were forming in May. When I move and plant things in the fall they don't start to grow roots until the next spring/summer.

There is a thread on the board somewhere where I was showing that root growth in summer, after dividing some plants of Potomac Pride. I'll try to search for it.

Hope that helps.

Chris

[Chris_W]

Here is one of the threads that I mentioned:

viewtopic.php?f=1&t=51790

[plantswoman]

Hello Tigger, thanks for the link, and Chris thanks a lot for the detailed answer and the thread with those great pictures.
So, always new things to learn. So far I always tried to transplant perennials in autumn, probably ok for European species (cold season mostly, I assume). And I will watch my hostas closely. One big clump of Francee will show, whether I got the timing right. I rescued it from a building site around June, so hopefully it made lots of new roots and should be able to grow large leaves (as this year) next spring. Another one is a small division of June I got at a plant swap. The leaf stalks had broken off in the process so I got just a bare bit of crown. It grew some new small leaves which are still green, so hopefully the roots did a similar thing.

Thanks again, cant`t wait for the next spring,

yours, Anna