I'd opt for cruelty and stop watering them. Unless you're expecting to be without rain for a month or so, or they live under the eaves of the house, I'd let them take their chances on whatever the clouds send.

I wouldn't feed them much, either. Slow release in spring is about all. As much sun as you can provide - including hot afternoons. They live in cracks beside the tarseal on the road, have enough leaves to get by - and do flower, so assume they're fairly thrifty. (I mean, no one from the highway roadside department ever goes out to feed or water them here!)

They will flower in part-sun but tend to produce heaps of greenery, too.

Mine is flowering now. I've had now for 5 years and except for the first (it was an abused specimen when I adopted it), it has flowered profusely every summer. It sounds like you are doing everything correctly but that obviously isn't working. I would confirm that indeed, your garage is cool enough...look for Good luck next year
Simon

Hi Judith. My agapanthus is in its second year and is blooming for me now. I overwintered it in the basement and started watering it again in mid March. I understand that they do like to be rather rootbound. I keep her moist and fertilize every week or two with 20-20-20 fertilizer. Mine gets about 8 hours of sun.

Here they are not usually potted unless in transit. Three years ago I lost the name from a potted plant and could not identify it as it did not bloom but did multiply. I repotted into three pots and when through another season with no flowers. This spring I said if you don't bloom this year you go in the compost pile. Although all the pots were full to bulging I left them sitting in the sun but watering normally. I was surprised when all three bloomed and were agapanthus which I had no memory of potting up. So I have to agree let them get pot bound and if in a china pot it should be one with sloping sides so it won't break the pot. Al

I planted a Agapanthus (Headbourne Hybrid) in 1999 in red-clay soil. I leave it in the ground year round. The Agapanthus has bloomed every other year. The number of plants increases each year. Fall, 2005 was very dry for us, 2005-2006 was a mild winter, lots of rain this spring. The plant receives 7 hours of intense sun. I fertilize it with a bulb booster in the spring. I would like to see more than 1 bloom.

Thank you all so much! You have given me many suggestions, and I will try to take a little wisdom from each answer.
Alex, debbie, & vetivert: I will find more sun somewhere LOL - because after l:30 (6 hrs sun) it's in the shade (needs that HOT afternoon sun?!) and yes, Alex, it sure is hot enough here for me - we're in the middle of an intense heat and humidity wave!(that's why I'm hiding in the basement,and on the computer!) Also, maybe I will let up on the water a little. The roots do seem to be filling the pots up nicely, so I'll leave them there for now.
Simon: I didn't know they needed light in the winter, so that could definitely be one of the problems! They've been kept in a corner in the dark! I already have a light set-up in the garage, so I'll just move them over there.
Al: Finally, I will threaten to pitch them into the compost bins if they don't perform! It seemed to work for you! And don't be so sure they don't understand - I threatened a Japanese Hydrangea vine with one more year and you"re gone, and this June, after 6 years, it finally bloomed, and it was gorgeous!
And Allium: I wish us BOTH luck with our plants next year! They keep saying patience is a virtue, but sometimes it's hard......!