Look through the drainholes underneath and see if they're full of roots. Hopefully they'll not be and you'll have a few weeks grace before potting on.
This is the problem with mail order plants - you have no idea in what conditions they have been raised. The very nature of plug plant production is very fast, very high turnover. So the chances are that they are young divisions from plants kept in spring like conditions under glass. C.glomerata is fully hardy, but young divisions like this will need protection. So I would keep them in a cool spot/room with lots of light.

What sort of area are you hoping to fill? This plant spreads quite nicely, but not uncontrollably, so in a couple of years two plants will fill a 0.5 square metre area.

Excellent reply Meanie!

Nice to see a question that I can answer Kildermorie!

It winds me up that these plug plant suppliers do not make clear what is needed in terms of care once the plant arrives. Particularly frustrating for plants such as this which can be picked up for £2.50 for strong hardy grown specimens in 1 litre pots from independent nurseries.

I am happy to buy seeds online, but things like corms, bulbs, and plant plugs that I can't see before I buy I steer well clear of, even from reputable suppliers. I once bought 10 begonia tubers from Thompson and Morgan online, they were undersized, only 3 of them ever grew, and the plants themselves where not top quality. OH brought some more back from his travels, bought at 2/3 the price from the little local GC, they were twice the size, and all of them produced beautiful, big, healthy plants. Sometimes these wonderful offers aren't so wonderful. These days I like to see what I'm paying for.

I'm with Gattina on this, having had similar experiences. I ''did' order some snowdrops in the green from an offer in the paper the other day. They were "free", i.e. you had to pay an inflated P&P charge, but were still a good price. I wonder what's going to arrive & what size they'll be..... I'm not expecting a whole lot from them - yet.

"which can be picked up for £2.50 for strong hardy grown specimens in 1 litre pots from independent nurseries"

or from outside my nursery for 75p!

Good gracious, Anchorman - I'm on my way!

I agree,I prefer to buy mine where I can see them..but realise everyone isn't able to always get out to do this..so it works for a lot of people..the P& P is sometimes very expensive,I notice..so I guess you have to shop around..

I'm on my way too Anchorman.

I wish that more people would kick the internet habit too. There are small nurseries all over that are struggling yet offer better plants on the whole.
Not always possible if we're after the exotics though........

THNAKS FOR YOUR ANSWERS I ONLY ORDER OVER THE INTERNET AS I AM AGORAPHOBIC AND CAN'T GO OUT TO CROWDED PLACES. I'LL JUST HAVE TO KEEP MY FINGERS CROSSED AS THEY DO HAVE ROOTS AT HE BOTTOM SO I GUESS I'LL HAVE TO PLANT THEN IN POTS NOW AND PRAY!

Selling to the public is a minimal part of my sales of plants.

My nursery is very small now. I sell perhaps 2500 one litre perennials per year compared with 40000+ shrubs/plants when I was a full time nurseryman 20 years ago.

I sell at the local auctions because it is easy,there are no bad debts and I can deliver 150-200 on a Thursday morning and it's over and done with.

Prices are usually very poor. Good quality one litre perennials like mine often sell for 40p but 200 times 40p is not to be sniffed at.

I live in a small village on a cul de sac country road so there's little through traffic but I sell 5-10 plants a week in the growing season by just putting them on a tray by the road side and trusting folk to put the money through my letter box which so far they've all done.

I know garden centres have big overheads but the mark ups are staggering.

Plants identical to mine often sell for 10-12 times more than I get at auction .

I've thought about doing car boots but being a full time gardener I haven't got the time and I'd have to travel at least 30 miles from where I live as most people in the Wisbech area know a nurseryman or know of the plant auctions there

I should be REALLY pleased to buy anything and everything from small, privately run nurseries, but it's knowing that they're out there, what they sell and how to find them! I've been really happy with everything I have ever bought this way, and much prefer to buy from someone who has actually raised the plants themselves rather than from big anonymous companies who have just imported them from Holland, and who know nothing about them and have no idea how to look after them. Is there any sort of publication that lists these little independents?

Italies equivalent of the Yellow Pages?

I should be able to get UK yellow pages online, I expect - good idea, Meanie.
Actually, just tried it with fairly useless results. I think it's going to have to be word of mouth.