I leave all my Allium seedheads on until they breakaway in the wind. Cristophii seedheads are most attractive. I don't really care if the bulbs come back the following year. Most are cheap enough and beautiful enough for me to replace them every year. :-)

My Globemasters and Gladiator multiply but the flowers get smaller every year, though.

If you don't cut the seed heads off of 'Purple Sensation', the parent plants don't seem to mind. BUT the dang things also seed like mad, and the seedlings are a bit smaller-flowered than the parent plants. You won't know this for 3 to 5 years, at which point you will have a purple lollipop farm. The seedlings are VERY low-key and easy to miss, especially in mixed plantings.

Right now I'm leaving all seedheads on in the front garden, where I could stand to have some more Alliums. The back garden gets deadheaded ruthlessly.

Lisa

Thanks! This gives me more to consider!!
Judye

Years ago, I planted several types of allium, and now, I find them growing in places where even weeds would dare to wander. I would like to get rid of them, but I've been over-ridden by my wife, who likes to use them in her dried flower arrangements.

Thanks, I appreciate the heads up!