Which species are the best for relentless summer heat? I planted some A. "apricot sprite" and A. ruprestris. The ruprestris is ok but wilts almost daily in the heat wave here. The apricot sprite plants look dead or nearly so. Both were planted last fall. The bed is full sun and gets irrigation. There are other perennials in there that look fine. I am disapointed with the performance of both of these plants. I do realize the drought and heat we are experiencing in TX this summer is severe but these 2 plants should be able to handle it with watering. A. cana is native to west TX, would it be a better choice for me? It might be a bit tall for where I want to plant it. Any suggestions/help would be appreciated.
Our heat isn't as relentless as yours, but I've grown both of those and they don't seem bothered by the heat (a couple years ago we got up to 115-117 for a few days, and every summer we'll have a few heat waves where we get into the 100-110 range). So I wonder if it's really the heat that's the problem, or if it's something else like poor drainage or your humidity? I don't know if A. cana will do better or not--I'm not super familiar with western TX, but my impression is that it's drier and less humid than your area so something that does well there won't necessarily do well in your area (it might be fine--but if your climate is different than its native area it's not a guarantee).
How often are you watering, and what sort of irrigation system do you have? I've found that drought tolerant plants tend to not do super well on drip irrigation, so if that's the type of system you have that could be contributing to the problems. Also, when did you plant them? If you just put them in this year and they didn't have a chance to get fully established before the heat set in then that could be the problem, but if you can nurse them through this summer then next year should be better.
A. rupestris and A. aurantiaca have evolved to withstand hot and dry conditions in the mid to upper elevations of mountains of southern Arizona and New Mexico and neighboring parts of northern Mexico. They also have experienced monsoon effects. I would expect them to be intolerant of high nighttime temperatures, especially during periods of heavy and/or sustained wet weather. Raised beds of easily drained soils would be of value to .help sustain these plants in adverse conditions.
They definitely don't like subtropical southeastern conditions.
The commonly described hybrids based on these species should also have these tolerances.
I think lack of night cooling is probably the problem. They are well irrigated and I have plants that require good drainage in with them that are doing fine (blackfoot daisy as an example). I am originally from the midwest and its hard to describe the heat here. It is months sometimes of 100+ temps and the nights are only slightly cooler. I just thought these plants would do well here. If they survive I will probably move them to less sun next spring. No rain to worry about the humidity is pretty low. I am certain it is not a lack of water. Thanks for your thoughts. Does anyone think A. cana might fair better?
My Navajo sunset just up and died, it was doing great, and within several days it turned brown and died. and it's been miserable hot here, but we are still below avg. rainfall, so I was watering it.
The Apricot Sprite which gets more shade than the Navajo did is doing fine as is Tuttie Fruitti, and Golden Jubliee, although T.F. is looking a little bedraggled, but that's not unusual this time of year. The major difference is that the Navajo Sunset just went in the ground this spring, where the others have been in the ground from 1-3 years. I think lack of being established probably had more to do with it, and possibly with yours also.
I'd say shade and raised beds with expanded slate pellets would optimize growing conditions for Agastaches, and also for tuberous Salvias as well, such as patens, lineata, clinopodioides, stolonifera, etc. The pellets also discourage attacks by voles.
I have raised beds and they get good irrigation. Shade isn't really an option so maybe agastaches just aren't on my list. I have salvias that do fine. I have a couple salvia in the bed with the apricot sprite and they didn't die this summer. S. regla, gregii and hot lips are doing fine in the same sunny raised bed where the apricot sprite all died and the ruprestris wilts. Might try them in another bed to see if they do better elsewhere in my yard.
I'll be looking for another Tuttie Frutti I guess, it's one of my favorites and the hummers love it. But these hot nights did it in. I'll plant it where it gets more shade this time tho...
IF I can find one around here. I almost always have to grow from seed or order Salvia's and Agastache