Digging and Storing Tender Bulbs

Digging and Storing Tender Bulbs

Part of Ep. 505 Putting the Garden to Bed

Store your tender bulbs over the winter.  Jeff Epping from Olbrich Botanical Gardens explains which bulbs should be dug up, when you should dig and how to store the bulbs so they can be replanted in the spring.

Premiere date: Sep 30, 1997

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
Dahlias come in many sizes, shapes and colors. They add beauty to almost any garden. But they won't survive a Wisconsin winter. Other tender bulbs include: Cannas, grown for their beautiful foliage, Elephant Ear Palladium, with brilliant light green large leaves, Tubers Begonias, popular in container gardens, and the delicate hues of Gladiolus.

We're at Olbrich Gardens in Madison. And I'm going to join the director of horticulture here, Jeff Epping, to show you how to safely dig and store these tender bulbs so they'll be ready to plant again next spring.

Hi, Jeff! It looks like you're getting this garden ready for winter.

Jeff Epping:
We sure are. We had a hard frost last night, as you can see by the Dahlias. They really take it hard. They start to turn black. And probably, in a couple of days, they'll just turn to mush. So, it's nice to get them out of the ground as soon as you can. It's not absolutely necessary.

Shelley:
So, if I'm running behind a little bit, how long do I have?

Jeff:
Well, until the ground really freezes. You know, the ground takes much longer to freeze than the air temperature.

Shelley:
So, we won't be killing the tubers by leaving them in a little longer?

Jeff:
That's right. We still have some time, at least until the first snow storm.

Shelley:
We hope!

Jeff:
But you don't want something like that around the garden when you've got Asters and Mums in bloom which really look nice.

Shelley:
Prettier stuff, sure. Well, why don't you talk me through what you're doing, then?

Jeff:
Well, we dig around the plant. Use a spading fork rather than a shovel because you have less chance of mauling the roots in the process.

Shelley:
And slicing them in half!

Jeff:
Right, so there's less damage that way. So, just pry around it. And as you can see, they're not really deeply rooted, so they come out pretty easily. We pull them out very gently and of course, the stems are very brittle and break. But you just try to knock off the worst of the soil.

Shelley:
You've got a lot still stuck there.

Jeff:
Yeah, and I'm not going to force it all out at this point, because I'll do more damage than good. When the soil dries, you can just sort of brush it away or crumble it away.

Shelley:
So, we could really hurt them. We should be real gentle at this stage.

Jeff:
Yeah, I think it's better to leave it on at this point. You can always wash 'em off with a hose or something later. So, when you get to this point, you can cut any stems that are left. You can see we broke off a couple, here. But, I'll just leave a little stub on there. You can always cut that off indoors when we go to prepare them for over-wintering.

Shelley:
And that's the next step, getting them ready for storage.

Jeff:
That's right.

Shelley:
Okay.

Jeff:
Okay, Shelley. This is another tender annual that we want to dig out in the fall. This is Canna. I think lots of people know what these are. They're very common.

Shelley:
They're very striking with a nice, tall statement, I guess.

Jeff:
It definitely is a nice full foliage in the garden. So, this is what Canna looks like when you dig it.

Shelley:
Enormous!

Jeff:
Yeah, very big. And often times, you'll have several of these. And that's why people tend to spread them around the neighborhood. But the nice thing is it's white, with no brown soft black spots on the bulb.

Shelley:
So, it's healthy.

Jeff:
Right. That's what we're looking for. That's ideal.

Shelley:
That's perfect for storage, then.
Jeff:
On the other hand, we have this Elephant Ear Palladium.

Shelley:
They have beautiful leaves. I love playing with them in the yard.

Jeff:
It really is a beauty. But this one isn't long for this world. We have some rot going on, here. So, if it were up to me, I'd just pitch this one. I don't think it's worth saving.

Shelley:
Okay, what if it's the only one you've got? It's from your grandmother!

Jeff:
Well, then... you definitely want to save it. What you do, is cut off the affected portions with a pruner or sharp knife. You want to sterilize them before you make the cut and after. Just use Lysol. That's something that works real well.

Shelley:
So you don't spread it to anything else, basically.

Jeff:
Exactly. That's important. And after you do that, you want to dust the affected portion with a fungicide such as Captan.

Shelley:
Dust the root?

Jeff:
Exactly, every root. You can do that to the wounds that you've created.

Shelley:
So, on disease and places like where we hacked off when we were digging it out?

Jeff:
Right. When I dug with our spade or our fork, I did knock a few off. That's not uncommon. So, again, just cover those with a little bit of fungicide. Just be careful, it is a pesticide, so follow the instructions.

Shelley:
Read the instructions!

Jeff:
Exactly. Now, with all of these, too, after you dig 'em and maybe apply the fungicide, let 'em cure for two or three days.
Shelley:
So, we're letting them kind of harden off, toughen up a bit?

Jeff:
Exactly. So, just keep 'em dry, not freezing, not extremely high temperatures, just enough to dry off all the portions of the root.

Shelley:
And then I suppose the extra soil comes off a lot easier then, too.

Jeff:
That's true, brush all that off.

Shelley:
And what do we store them in?

Jeff:
So, once you have your nice healthy root-- here's our Canna-- And here at Olbrich, we just use a Ziplock or polyethylene bag, it could be a garbage bag. And we use dry peat moss. And this is, like I said, dry. There's no moisture in here, we didn't add anything because we want to just preserve the moisture that's in the bulb. So, we just plunge it in there and cover it up.

Shelley:
Kind of bury it.

Jeff:
That's all there is to it. You can also use Perlite, Vermiculite, wood shavings work equally as well.

Shelley:
I have these handy. I live near a cabinet maker and they work just fine for my large Canna bulbs.

Jeff:
You bet! It's cheap, too.

Shelley:
Are there things we shouldn't use?

Jeff:
I wouldn't use-- Don't put them in soil. Don't put them in compost. A lot of times, if your compost pile hasn't really gotten hot enough, there'll be fungal spores that can infect...

Shelley:
And we don't need any more disease brought into it.

Jeff:
Exactly.

Shelley:
Let's talk about temperature and actually where we store these containers, then.

Jeff:
Sure. We're talking about 45-60 degrees, something like that. As long as it isn't freezing and it's not too hot. Here at Olbrich, we store them in a basement of an old pump house. We don't supplemental heat it, it just maintains good temperature.

Shelley:
I'm at the opposite end in my basement, it's 60 degrees year round. And they seem to survive every winter I've stored them there. What about light?

Jeff:
We want to exclude light if we can. Sometimes if they get just a light bulb on even, it will cause them to start growing again, particularly when you get closer to spring.

Shelley:
So, cool and dark.

Jeff:
Exactly.

Shelley:
Okay. Anything else we should know about?

Jeff:
It's not a bad idea to label the bag, the box...

Shelley:
Or both!

Jeff:
Or throw a label in, so when you pull them out the next spring, you know what they are.

Shelley:
Okay, thanks Jeff. So, if you do this right, you'll be ready to plant these out next spring. But remember to wait until all danger of frost is past.

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