Expert: Long Island Gardener - 11/27/2008

Question
QUESTION: We had a freeze the other nite that lated for 2 days.  I had A. Foeniculum (Lavender Hyssop)in planters that froze.  They are a very hardy plant that came back the year before after wintering in the ground. I was unaware that these are considered perrenials and could be taken out of the ground, then the root stored inside.  But now that it is back above 32 and are not frozen, I was wondering if I could try to salvage them.  What is the proper way to store these plants since they are considered somewhat of a tuber? Lavender Hyssop in the ground came back from the very base of the plants stem the last year

ANSWER: Agastache foeniculum, aka 'Giant Hyssop' or 'Anise Hyssop' (unless you're on the Seedland.com website, which refers to it primarily as 'Lavender Hyssop'), is a tough plant hardy to Zone 3.  This plant is SO easy it grows wild, which is why you can buy it in bulk on Seedland.com.

You did not tell me where your planters are or how cold it actually got when everything froze, but I suspect this was an early season surprise -- first frosts tend to be unexpected -- and the foliage/stems were felled but not the underground plant parts.  Since they were outdoors, they are most certainly hardened enough at this point from being acclimated to the onset of Winter.  That's important.  And it is the key here to whether they will survive having endured this initial test of toughness.

I would prefer that you leave the roots undisturbed and in their planters, where they have been growing happily for months.

Here's why.

The natural habitat of Agastache is not well understood yet by ecologists or botanists, as is the case w/ many native plants.  Wildflowers tend to be unpredictable and fickle.  Many botanists believe it is the tenuous state of their root systems and relationships with beneficial Fungi, arbuscular Mycorrhizae, which are destroyed in an instant when you disturb the roots they surround.  These species depend more than hybrid plants on those invisible bonds that get them growing in the most hostile landscapes, without water, without reason.

Mycorrhizal relationships are still a new area of intense study.  Ecologists consider beneficial Fungi a key to saving many nearly extinct species.

It is likely that even in your little pots, those Fungi developed around the roots of the Agastaches growing in them.  Unlike heavily crossed hybrids, they depend on the ten-fold fortification those Fungi provide.  You should over-winter them with careful consideration to protecting the roots and their Fungal friends.

Move the pots someplace just above freezing -- an unheated garage perhaps, or protected garden location where the Soil will not cool below 32 degrees F.  The biggest problem with freezing is the freeze/thaw cycle around the roots, which damages the roots.

Also, make sure those roots dry out every now and then.  You don't want root rot to pick up any steam around these plants.

Any thoughts?

THE LONG ISLAND GARDENER


---------- FOLLOW-UP ----------

QUESTION: I will move the majority of the Agastache plants as you suggested and not up root them.  But I am doing an experiment that I will share if successful.

 Some of the plants have been uprooted already.  I shook as much dirt off of them as possible. I put them into a black plastic bag under a sink where it is cool and dark and dry.
 I know that A. Foeniculum is a very hardy perennial, seeds that were planted started to come up right after the last frost of the spring.  I just want to see if the plant will come back from root that was wintered inside since I had a total of about 50 plants in various soil.  Some were in sandy humuous as potted plants, some were in red clay-type farm soil that were in my rented garden plot that grew to almost 5 feet tall with stems a wide as a cigarette lighter.  Now I have plenty of plants to experiment with and am keeping a mindset as to where they were growing and want to try wintering some of them under the sink and I would suppose keeping them as dry as possible. Let me know what you think I should try, remember this is an experiment, I have plenty of plant roots to try this with.  What would be the best approach as suggestion if I were to place them inside, without dirt and try to revive them in spring by replanting.  First you tell me that they are so easy to grow and then say they have intricate microorganisms in their root structure that create a symbiotic relationship.  I just want to see if I can preserve some of them like a bulb or tuber, what would you suggest.  Thanks !

Les

Answer
First, I think you ought to switch those plastic bags and use paper bags instead.  The aerobic environment of the plastic bags is unhealthy for the roots and may damage or destroy them.

I did not mean to confuse matters with respect to how easy, or hard, these are to grow.  If you consider that those intricacies of the roots take place on their own without orchestrations by Man, and that they thrive on neglect, these are in fact quite simple to master.  Leaving them alone in the ground to get by pretty much qualifies them as an easy plant, wouldn't you say?

But when you start moving the roots around and transplanting them, things do begin to fall apart.

All of these tests you are doing are capital ideas, if I might say so.  Some will be better than others, as you've discovered with your tests on Soil etc.  I do not think they have yet isolated the actual Mycorhizzae responsible for those symbiotic relationships, but without them, the plants do less well than those with them.... usually.  Who knows what else you'll learn here?

Please keep me posted --- inquiring minds want to know what works, what won't.  Thanks for writing.

THE LONG ISLAND GARDENER