Over wintering agapanthus

[Cgull49]

I purchased an immature pot of agapanthus this fall and am wondering how best to carry it through the winter.  I've not watered it since early November and it's still sitting in it's pot in my dining room.  The leaves are starting to yellow.  Can I now put it into my basement, which is probably around 15-18C and leave it in the dark until say the end of March or should I be doing something else to it?

[Paddy Tobin]

Rob,

It was only when I saw that you were posting from Ottowa that I understood why you were asking such a question. Here, south of Ireland, agapanthus get no special treatment at all even the evergreen more tender ones.

Sorry not to be of any help.

Paddy

[Lesley Cox]

I imagine that if it were confined to barracks through the winter, ALL the leaves would quickly go yellow. Put it somewhere cool (they can take a fair amount of frost) and it will maybe lose its leaves but shouldn't die. Don't water if it's not growing. My personal choice would be to heave it into the nearest rubbish bin but then, they're just about noxious weeds here. I had one sit bare-rooted on my potting bench for two full years a while back. The damn thing started to grow when I threw it onto the compost bin!

[Anthony Darby]

I put my potted ones under the staging in the greenhouse from December to March - temperature about 4^oC. Those in the ground have survived a number of years, but then we have only had -8^oC minimum since for the last few years. I would have thought that 15 - 18^oC would be on the warm side for dormancy?

[David Pilling]

I've just chopped the leaves off the agapanthus, they're now in the garage - not heated,  temperature above freezing but usually less than 10C (50F). When it warms up in Spring they start to grow and I'll  move them back into the light.

In other words at 15-18C they will start growing.

[illingworth]

Rob, if your plant is quite small I think I would try and keep it growing inside through the winter, either in a cool bright window or under lights. Then pot it on in the spring, put it outside for the summer, and then in fall, after a couple of light frosts, bring it back inside and winter it in the coldest part of your cellar. We winter ours in our coldroom, where the temperature might start out around 10C, but is now down to 5. They will lose colour, but the leaves will green up and start growing once outside again in the spring.
Just plant these either in a plastic pot or a clay pot to which you are not closely attached. We had ours in a clay pot at first (they do like to be potbound), and when we came to repot it, after a futile struggle with knives, sticks, and the garden hose, we had to break the pot !
Sharon

[Katherine J]

Hi Rob,
I'm in zone 6 in Hungary. I have a friend who has many Agapanthus, because he grows them for flower shops.
In the end of october he puts them in the cellar, where is no light and 4-5°C, and does not water them at all. He brings them up to light in april, or it depends on the weather. Repots them in fresh compost, and so on.
Good luck!

[Cgull49]

Thanks for all your suggestions.  Obviously this plant is tougher than I thought.  Right now in Ottawa it's about -5C and we've just come through a couple of nights where it has dropped to about -15C.  When winter really hits it can easily get to -25C or colder.

I'm in the process now of building a small heated insulated box which I will keep outside. I will use it to keep things like begonia tubers, young plants, which don't have enough mass to be hardy through our winter and agapanthus.  I'm planning on using one of those electrical cords that can be wrapped around water pipes to keep them from freezing in the winter.  The included thermostat is set to maintain a temperature of around 4-5C, which seems just about right. My design requires that I keep the cord away from the bottom of the wooden box and covered with sand.  An old metal tray from the bottom of a dog crate will both hold the sand and separate the cord from the bottom of the box.

I'll keep the box in my garage close to the house and hopefully pick up some additional warmth that way.  I also have one of those wireless thermometers, which I can insert in the box and read the temperature from inside the house.  So as long as I use sufficient rigid styrofoam insulation to keep in the heat, I think it should work just fine assuming it doesn't have any significant air leaks.  Any thoughts?

[ChrisB]

Isn't it funny how we all manage to find some plant to love that doesn't really relish the weather conditions we live in?  I'm just as bad wanting to overwinter things that really hate the damp weather we get here in Northumberland over the winter.  I always think I'm going to be more sensible next year, but as we all know, next year never comes.....  So good luck with your agapanthus in chilly Ottawa.  I used to live in Ontario and know the awful cold winters you have there all too well.  That's why I came back here in the end.  The gardening season is just too short over there for my liking, though I do miss those wonderful tomatoes I grew in the heat and humidity of the summer.  Ah well, we can't have everything....

[samsgarden]

Hi Rob,
From another Zone 5a Ontario Agapanthus lover...........
After years of dragging in two pots of Agapanthus, grown from seed, every fall I planted one next to my cold frame two years ago.  Covered it with old hanging planter soil, torn cocoa fibre and leftover spruce branches from a Christmas urn arrangement.  Surprisingly it was tough and came up again and flowered to boot!
My basement floor is 4 to 12 degrees C throughout the winter. I watered the pots occassionally but probably didn't need to.  If I had your young plant I'd probably treat it with more warmth the first year! And your thermal box sounds perfect.
After a few years you'll find pot bound roots.  I suggest you plant some of them as an experiment.  I have heard Patrick Lima has had Agapanthus in his Zone 4 Tobermory garden for years!

[Maggi Young]

Hello, Samsgarden! Glad you have decided to speak out! Hope this winter is good to you and your agapanthus 

[Anthony Darby]

I'd be surprised if Tobermory was as low as zone 4, being influenced by the North Atlantic Drift?

[ChrisB]

Hi Anthony,  I think they are referring to the Tobermoray in Ontario, and it certainly does get very cold there.  Were you thinking of the original one in Scotland perhaps?

[Cgull49]

Samsgarden,

If Patrick Lima can overwinter agapanthus in his garden in Tobermory, Ontario then I probably can do it as well since we are both in Canadian climate zone 5a. My site might a bit warmer than that since I live in the city, although not downtown and am fairly sheltered. I'll certainly have to give it a try, although maybe not until I'm able to split the aganapathus I have or acquire some more.

Rob

 

[Robert Pavlis]

I live in Guelph Ontario - Zone 6 Canadian. I let the plant receive several light frosts in the Garden. Then cut off all leaves - by now mostly mush. I keep it in the garage to keep it cool until Dec. Then it goes into the fruit cellar. I might add a bit of water once all winter. Take it out in early spring.

I have tried to keep part it in the garden one year, but it did not survive.

In summer I only submerge the pot half way. It keeps it drier, and this plant seems to flower better with a bit of punishment I think it likes the extra heat as well.

The first year I had it I tried to keep it growing all winter under HID lights. It did OK, but not great. The next summer, it did not flower as well.

I don't know the variety I have, and some are hardier than others. But I would be surprised any of them would survive outside in Zone 4?.