In a warm enough zone, this Agapanthus would not die back to the ground in the winter (another sort does). Ideally, you would allow it to continue to grow in a cool (5-10C) greenhouse, but most of us do not have a greenhouse so we have to make do. If you can give it a nice bright window, away from a heater, it might do well as a houseplant for the winter. You could also grow it under fluorescent lights.If you can't do either of those, then you should allow the plant to die back in its pot and store it somewhere cool. It will need to be kept from drying out, so an occasional watering will be needed to keep the soil from getting too dry.

If you keep it as a green houseplant, do not fertilize it until early April (?? maybe earlier or later, depending on when you can start putting it out again in the spring). If you allow it to die back, start watering lightly couple of weeks before you would start putting it out and fertilize as soon as you see growth above ground. The chances of it surviving if it dies back is pretty good, as long as you walk that fine line between keeping the soil too damp and too dry :-)

BP

Thanks so much BP. I am not sure what I will do with it, but you have given me the options...thanks again.
Lois

Another question that I hope someone can help with is about the planting depth. When I got the plant, the bulbs were not totally buried...about half out of the soil. It did fine like that for thecouple of months after I brought it home, but now I repotted it into a different pot and buried the bulbs a bit deeper. Should they still be a bit uncovered or is burying them okay?

Hi Greylady..
If your dwarf blue lily of the nile is the species Agapanthus, I would like to offer a suggestion or two.
I grew the regular seeds, obtained from England, some years ago.
I put the plants in my cold basement for the winter under indirect fluorescent light and watered once a month.
They became pot bound after several years and very heavy. So I planted one in the ground and covered it with old hanging pot soil, leaves and evergreen branches come January left over from Christmas pots, wreaths, etc.
I'm in Zone 5a and temperatures reach -30C at times. Also we have lots of snow cover January on in this particular spot.
The Agapanthus survived and bloomed the following summer!
I still bring in the remaining pots so as to cover the possible loss of the one outdoors!. The tuber like roots multiply quickly. It seems they like to be root bound before blooming!
Have you heard of Patrick Lima? He has several garden books written.
In their Bruce Peninsula Zone 4 garden, he and his partner successfully winter Agapanthus using the above method....4 to 5 inches of cover.
Sharon

Sharon - that's really interesting! I have never heard of anyone overwintering them in our zone. I think I'll try that with some of mine this winter too.

qreylady - these plants are known for becoming pot bound and even 'crawling out' of the pot they're in (several people have reported their pots have broken from the roots growing too large for the pot). Exposed bits of tuber won't hurt it at all while it's growing, but if you let it die back you might want to cover it up a bit so that it doesn't dry out too much.

BP

Just thought of another material to 'cover' tender or higher zone plants.
The cocoa fiber liner of hanging pots, when worn out, act as a blanket!
Sharon

thank you Sharon and Bonniepunch. I still have it in the larger pot and the tubers are covered. The foliage is looking a bit spotted with yellow, but it did receive a shock with the transplant and being brought indoors, so I guess it really doesn't look too bad, considering.
I will check the info that came with the plant and see what it says about what type it is. I could be convinced to try one outside for the winter under very protected conditions if I get it to the point that it needs to be divided and I have one to "spare".