The best time to plant rosemary is in early spring (like late feburary early march). Planting in other parts of the year could cause problems for it, but it could live if it has the right conditions. Fall might work too, but it's still pretty hot at the start of fall, so it's not optimal. They need a good amount of time before summer to set roots, and they need a lot of sunlight, which is bad for a new plant in summer.

You do have to give them water at least once a week when you first plant them, but once they're actually established, you never have to water them. I have 4 huge rosemary plants in the back yard that I planted 3 years ago and I can't remember last time I've given them water. (although that's not to say they don't need water, they're most likely getting a little water underground from other plant watering)

When did you plant it, and how were you watering it?

Planted it in a large pot in June and watered it from the top three to four times a week. After your awesome advice i think I planted it too late and it didn't get established. Plus watered it too much, I'll try again in the fall. My New Mexico Master Gardening course wasn't helping me much here in AZ...had a beautiful Rosemary plant in NM.

I have one that is getting tall and falling over. Should I stake it up or should they be trimmed down short. I don't know how they are supposed to grow or hie big.

It depends on what kind you have, but most of them do tend to sprawl all over the place. You can trim it back to keep it more compact if you want.

Pots tend to overheat in AZ. Plant it in the ground, or use a double pot.

And use a moisture meter, not the calendar, for watering. You might have been over or under watering.

I've grown a few Rosemary plants here. It's only been a few because they live for years even if neglected. I cook with rosemary regularly and a single plant still always well outgrows my cuttings.

A couple things I have noticed that will hopefully help you are that they should go into the ground ASAP in the spring. Plants in my raised beds always massively out preform those in pots. Watch out for spittlebugs when they are very young. Once established they won't do any real damage. Spittlebugs look like little fluffy clouds of white spit basically. They will only actually damage the plant when it's still very small and are simply removed with a spray from the hose. Rosemary prefers an organic decently water retentive soil with little to no added fertilizer in my experiences. And the absolute best thing about Rosemary is anytime I spray it from overhead with the hose, dozens of green lacewings come flying out. They seem to love using it as refuge during the heat of summer.

Oh and fwiw, mine are usually in a bed that gets watered daily from drip sprayers and has never had a problem with over watering.

Good luck

3-4 times a week might be too much for that plant. In my experience it hates frequent watering.

I've grown rosemary in both pots and raised beds. Even though planting in a raised bed gives you a larger plant, a potted plant can get big enough for our family of four's culinary use. Keep in mind that lighter colored pots are better so you don't cook the roots - never use metal. I agree with everyone else - you probably started too late and watered too much. I've planted in early September with success so you don't have to wait long to get started. Once established, rosemary will survive pretty much anything Arizona will throw at it. I gave one I potted to my mom and it lived, so there's proof right there.

My experience with rosemary in the desert suggests I could set it on fire without killing it. Once it's established, of course. Plant it in ground in late January, and let nature take its course.

I planted 2 of my 1 gallon rosemary in early April of this year and now they're trailing over the sides of the planter. (more than 5 times original size) The soil is straight Kellogg raised planter soil. They were hand-watered at first, but have been on a 20 minute drip everyday from May-Sept and every other day since then. I dead-headed quite a bit in the early days but haven't had to in a while

^That shows how tough Rosemary is. But it may not survive that level of over-watering forever...

Rosemary is used in commercial plantings all over the Valley and grows like a weed....it cascades down retaining walls and planters and covers ground in parking lot planters. It loves heat and thrives without much water.

I am confused about the comment of deadheading........just exactly how does one deadhead a rosemary? (and why??) btw, I've grown a single rosemary plant for more than 30 years here in the very damp (in winter) PNW. They are an extremely hardy and durable plant under even somewhat adverse conditions. I've also never 'deadheaded' one (never seen a need for that technique!) but prune it back often to keep it within bounds. It's about 6' x 6'.