No, alpine plants do not need a lot of water. Watering alpine plants the way you water a thirsty border plant is the fastest way to kill them. They want a sip now and then, not a flood, and for most of the year they cope fine on rain alone. If you give your alpines less attention than your roses, you are already on the right track.
One March I lifted the lid off a trough by my back path and found a cushion Saxifraga gone soft and black right at the crown. The tight green dome had collapsed in on itself after a soggy winter, and the neck pulled away with a wet tug. I scraped off the rotten part, reset the plant proud of the surface, and packed sharp grit tight around the neck. By June it had thrown fresh rosettes and held them through the next wet spell.
The reason sits in where these plants come from. Alpines grow on gritty mountain scree that drains in seconds, so their roots almost never sit in standing water. When you give them a heavy, soggy soil instead, the crown stays damp, and that damp neck invites collar rot. That rot is what blackened my Saxifraga, and it kills far more alpines than any dry spell ever will. So your first task is not to add water but to make sure water leaves fast.
Most alpines are drought tolerant alpines by nature once their roots reach down. An established plant shrugs off weeks of dry weather because it stores water in fleshy leaves or sends roots deep after it. You will see this in your own bed within a season or two. The plants you fussed over least, watered least, and left to fend for themselves are the ones that look best.
Water in well at planting so the roots settle. After that, water only during a prolonged dry spell of two weeks or more. The rest of the year, let the rain do the work for you.
Good alpine plant drainage is the real secret to keeping that neck dry. Plant your alpines into a 50:50 mix of compost and horticultural grit so water moves straight through and never pools. Then top-dress with a layer of gravel right around the base of each plant. That collar of stone pulls moisture away from the crown and stops the neck sitting wet, which is exactly where the rot starts. If you do nothing else, get this part right.
You can spot trouble before it spreads if you check the crown now and then. Push a finger gently against the base of the cushion. A healthy alpine feels firm and springy, while a rotting one feels soft and gives way under light pressure. Catch that soft patch early and you can often cut it out and reset the plant high, just as I did, before you lose the whole thing.
Containers and troughs change the sums a little. A pot dries out far faster than open ground. So a trough alpine in full sun might want a soak every few days, while a border plant wants none at all. Watering alpine plants in pots takes a touch more care for that reason. Check the grit on top before you reach for the can. If it is bone dry an inch down, give it a drink. If it still feels cool and damp, leave it alone and come back tomorrow.
So plant them sharp, top them with grit, and then mostly walk away. Step in with the watering can only when a long dry spell hits or a pot turns dusty. Keep drainage first, watering second as your rule and you will keep those tight cushions tight for years, with far less work than a normal flower bed asks of you.
Read the full article: Alpine Plants: A Complete Grower's Guide
