Unlike rhododendrons, azaleas have dormant growth buds just under the bark all along their stems. They will sprout from just below any cut you make. While they normally don't require pruning other than to remove broken or damaged stems or that occasional stem that throws the shape out of balance, if healthy they will respond well to the heavier pruning you describe.

This isn't the right time of year though, azaleas set their buds for the following Springs blooms in summer and pruning now would remove next years flowers. Better is immediately after bloom.

Rather than start a new thread re pruning I shall post here and hope for a reply.

I have several Azaleas in pots, they are just coming into flower now so I know I have to wait till they have finished flowering before pruning but...they didn't get off to a good start and lost a lot of leaves up the stems of quite a few. I am wondering how hard can I cut them back or should I leave them be and they will eventually fill in themselves. They are very small plants.
Thankyou.

If they are very small plants, I don't think I'd prune but wait to see what they do if provided better conditions.
Healthy azaleas will normally respond well to hard pruning - none should require it when small. Do you know what was stressing yours? Potting mediums for containerized azaleas should be quick draining and porous, allowing good aeration for the roots but must be kept damp - moist without ever becoming soggy. Watering of potted azaleas takes some attention. Their fertilizer needs, unlike those planted in the ground, must be met too - a liquid product that can be mixed with water usually safest, it's easy to burn those surface roots with a dry or granular product.

Thank you for responding.

When I potted them up I didn't put anything over the holes in the pots, I think the drainage holes may have blocked and they got too wet. I have repotted them, added some different size gravel to help drainage, covered that with shadecloth to prevent the soil getting thru and then popped the plant back in. I have also raised the pots off the ground and mulched with pine bark. They are now flowering and putting on new growth, but only at the ends of each branch. I used a slow release fertiliser, will use liquid in future. They are all in terracotta pots.

mrsmuggleton: quite often the indica azaleas look like death warmed over during the winter and start to come away in spring again when they put out their summer leaves.

If you pinch out the ends that have flowered, pretty much straight after the flowers have dropped, and feed with liquid fertiliser, half strength, each month over the summer to boost leaf production.

They'll need morning sun over the summer to set the flower buds for the next spring. Otherwise protect from afternoon sun and from droughting out.

If the terracotta pots you're using are the plain ones - did you put pot paste on before you planted up? Or are they glazed? Otherwise they can dry out very quickly.

If you bought your azaleas recently - it takes ages for them to settle in and colonise the pot with their roots. (Think months to even years.) A plastic pot can be better at holding moisture for them. For watering - plunging into a bucket of water can be more effective than overhead watering because their root mass is so dense. Wait 'til the bubbles stop and bring them out to drain (an old fridge shelf over a bucket can be very useful...)

Kurume azaleas tend to not go leggy like the indicas. If you do get an adventurous shoot - pinch it back to the height you want and it will probably resprout.

Satsuki and the gumpos seem to be more like the indicas - sort of sparse when young.

It's not likely to happen - however be sure to keep your potted azaleas away from things with floppy leaves. If they're caught under anything smothering then branches die back and it takes ages to bring them back into decent shape and flowering.

BTW - if you can get it, they quite like sheep pellets and crumbled cowpats, but not thickly applied. Use as a light mulch for slow release and fine humus.

Thankyou Vetivert8, very helpful.

The pots are not glazed and are way to big to dunk, but when I potted them up I put quite a lot of the water storage crystals in each pot and mixed well through the soil. They are all on irrigation with a dripper into each pot..I think they should be ok water wise.
I shall get a bag of sheep manure, hadn't thought of using a manure on them, though I have done so on Camelias in the ground.
They are all new this year, started potting them up in February I think it was, so maybe this summer they will settle in. I suspect winter happened before they got used to their new postion.