The Wool-carder bee, Anthidium manicatum, is one of my favourite bees. 

To start with, just to clear up any confusion, they're not a bumblebee. They're no relation to nice fluffy Common carder bees like this:

Yes, it's confusing. Sorry about that.

Wool-carder bees ARE particularly good looking though. They're one of our largest solitary - not bumble - bees, and have smart yellow spots down their side.

The males are bigger than the females, and have a comic beligerence. Like all male bees, wool carders are stingless, but they charge around their little territory boshing any other insect with a set of spikes on their abdomen. After each frantic encounter they have a short rest, then whizz off looking for another intruder. I spent a half hour watching this chap, who paused between patrols to sun himself.

There is always likely to be someone to see off, as Wool carders hang out around Stachys byzantina, or Stachys lantana - Lamb's Ears. It's a pretty plant from the Middle East, drought tolerant and easy to grow, and a good source of nectar for a number of other pollinators, not just other Wool carder bees. That's not principally why our friend values it so highly, though. The females scrape the soft furry hairs from the leaves to furnish their nests. Stachys lantana can give them what the native Great mullein or Yarrow also provide.

It's this relationship between plant and animal which I really like. I bought three little Stachys lanata plants in pots a couple of years ago and planted them to see what would happen. It took a season, but last summer - from nowhere, apparently - Anthidium manicatum rocked up. They're not particularly rare bees in the south, but I hadn't seen any around the garden for 5 years previously. We now have six patches of Stachys, which spreads like topsy, and - guess what - Wool-carder bees in all of them.

It's a small example of how we can make a measurable improvement to biodiversity by making an easy and apparently minor - but informed - change to our immediate surroundings. This is such a key message for us all, and it's not just important but immensely empowering.