Do not feed,do not touch them, neglect them completely-I posted a picture and discussion about this a while back- will post a link when I find it
If they are kept pot-bound they perform better-perhaps yours have not reached that stage yet?
Here you are-neglected for over 20 years
I read somewhere that a dose of tomato fertiliser now is a good idea so I gave mine some last week, otherwise don't feed and keep them potbound. Just protect their pots with bubblewrap and put in a sheltered spot for the winter. Keep them dryish over the winter.
'Last week' is too late in the year to feed deciduous plants; they are about to go into hibernation. New lush growth is very vulnerable to frost damage.
Caz8 wrote (see)
Please can someone help? I have 2 pots with 2 agapanthus in each, planted 3 years ago. Each year the leaves start growing, very healthy and carry on right through the summer, but where are the flowers. What can I do, or do I start from scratch?
How big are the pots that your agapanthus are in? As Geoff says, they do seem to thrive when potbound. They might do better in more confined condtions.
My suggestion would be look underneath?-are any roots poking through-other than that carefully tip them out-if the container- is full of root leave them be-18 inches is not super deep-get them in a sunny spot for next year and then forget about them.
At some point they will do what they are supposed to do
The week before last Monty Don said on GW to give them a feed and keep them well watered now til first frosts. I did not get as many flowers this year as i normall do but I put that down to the weather. They do like a nice sunny spot. I remember seeing huge pots of them on holiday in Corfu a few years ago and they looked amazing - getting baked in the sun and left to their own devices.
I had 24 blooms on my potted agapanthus this year and agree with sotongeoff that neglect seems to be the key. The pot is in a very sunny spot and the only treatment they got was plenty of water during the hot spell.