Too late to plant out? / Plant choices sound OK?

Paul449

Too much work (like most of us I'm sure) and plants flowering late (cosmos still going a couple of weeks ago and last dahlias cut for the house today) means I'm a bit behind.  Still a relative beginner too so lacking confidence.

I have plans for a 'dry' bed , because it's S facing and at the base of a Leylandi hedge, 4m x 1m, which I cleared today and could plant tomorrow but more likely next weekend.  I have 2 v healthy cardoons in 2 litre pots, 3 eryngium Miss Wilmott's ghost in 13cm pots, 30/40 allium sphaerocephalon, a dozen or so echinops in 13cm pots grown from seed and 2/3 well established Shasta daisies that are very happy there.  I could add some euphorbia (grow like weeds hereabouts - Lincolnshire) and I also thought of sedum and / or acanthus mollis to fill gaps (or is that too many plants?)

So... any thoughts on the questions in the title please? 

Posy

If it's at the base of a hedge you probably need to improve the soil before you plant because the Leylandi will have taken out every bit of good. I know you are choosing plants that like poor soil but yours is likely to be impoverished rather than poor! Once you have done that consider the plants: have they been growing outside for the last few weeks? Think about the weather, too. As long as the plants are hardened off and the weather is mild, they should be fine. Otherwise, you should wait for spring. Good luck!

Fairygirl

I'd agree with @Posy. If you can get some good compost and well rotted manure into the bed, that will help with getting plants established. It's fine to plant as long as the gorund isn't waterlogged [not likely there!] or frozen, so just pick  a suitable time, assuming the plants are already well established etc.
I'd still be inclined to wait until spring, when plants really want to grow. The ground should also be more hospitable after some winter rain. The alliums will need planted though - but you could put them in pots just now, which can then be planted as a whole clump. 
You may have too many plants, but you may also find some will grow less enthusiastically due to the conditions, and some will grow better. That can be remedied later though, and many of us have the same situationw - hen plants grow bigger for instance, than is often described.