Too much shade wouldn't cause failure of a plant during high temperatures, if anything the problem would be not enough shade. Otherwise it may be significant that this rather ample looking local offering includes several Brunnera but no Astrantia:

Perennial from Sandy's Plants

My brunnera seems ok in the heat but would like more water than I give it... but it survives. Astrantia does not survive. Unless you have a soil with steady moisture I think you would just watch it die again.

Thanks katob! OK, maybe I will try Brunnera one more time- it was getting some reflected heat from our light colored house too, I think. I've been thinking about setting up drip irrigation (I'm so sick of endless watering!!) we'll see...

Thanks again,

Katie

Thanks Embothrium! Sorry, when I said light shade I meant that to mean more shade than partial shade (in my case that would specifically be mostly shade but dappled light through tree branches). Thanks also for the resource of sandy's plants in VA. Good point- no more astrantia for me! thanks for helping save me some money:)

Katie

It's not so much the heat and humidity, its the moisture level. Brunnera will fry if the soil is too dry and possibly go dormant; same with astrantia. These are both part-shade/shade plants up here in the north -- so absolutely need at least part-shade where you are.

Thank you mxk3! I take your point, but I do want to mention that I'm pretty sure I never let these plants dry out- if anything, I wondered if i had overwatered (especially the Brunnera as it was in a pot). I heard that Brunnera is sensitive to root rot, so i was afraid that maybe I did do that?? So, while I didn't water the pot every single day I did check its moisture level every day. Well, anyway i did something wrong! Shade is no problem for me at all (partially wooded backyard and two huge trees in front yard), so I think I will give this plant one more go in a shadier location:)

katob description is what I see re astrantia; such an exquisite flower but the plant very much needs more water to look its best.

Thanks rouge21! It is possible that not enough water was the cause, but I'm a fairly obsessive gardener . . . so that's why I was looking for other possible factors. I just thought of something else that died! Ligularia. Well, 1 of 2 survived but it was doing poorly by the end of the summer. These plants were in shade, too, but they did get a little hot afternoon sun through the slats of the fence. Everything else around them did fine including hostas, ferns and astilbes, but these plants wilted every afternoon and giving them a little water to cool them off didn't seem to make much difference. Sigh, however hard I try, I'm just not very good at gardening:(

Katie, if you're growing astilbes in northern Virginia, you're a far better gardener than I.

Both plants are usually most recommended for cool summer climates and disliking heat and high humidity.....much the same as hybrid delphiniums. Why all are so common in UK or PNW gardens :-) You can grow them but they may not perform as well or be as long lived in locations that have extended periods of summer heat or high summer humidity.

Even here in MN Brunnera can be a bit challenging for nurseries to keep alive in the summer in containers once the heat and humidity kick in. They generally do fine as landscape plants around here.

Cecily- Only in full shade do I have success with astilbes, but don't worry, I've killed those, too:)

gardengal- thanks, I feel a little better now:)

How I long to live in a climate with cooler summers and no clay soil. . .

Thanks pennlake- I'll probably regret this, but I'm going to try brunnera just one more time. This time in full shade (just a couple hours of light) and only because I saw them for a really good price at bloomingbulb.com- couldn't resist:)

Frozebudd- Gorgeous! I wish. . .

Katie, I was following this thread when you first posted since I too had purchased astrantia in hopes they would survive in shade even with heat and humidity. I’m here to say that two I planted last fall never returned and one bought this year is on its way out. I also have two ligularia bought this spring that are in shade and are the same size they were when I bought them and the foliage is getting ratty. I had several brunera for a few years but no signs of them now now. I read they were short-lived.

I’ve had the same experience with some geraniums, including Rozanne. Ive planted it in full sun, morning sun, part shade, shade. It just peters out. Dont think I’ve ever had a picture worthy display.

You live, you learn.

This thread is old but just wanted to say that I’ve had lots of good luck with brunnera in part shade and consistent water. In direct sun, they fried. First year with Astrantia. Four of five survived the summer. Based o. This thread, I’m going to move them to shade as they haven’t grown much.

Not a hope with any of them. Total fails in sandy dry soil (obvs). My neighbour grows astrantia but practically knackers herself with continual watering. Primulas are another hopeless case...but in this case, I am exactly the same as my neighbour with the ever-present watering can, welded to my hand.

Oh I’m planning to try primulas this year. I hav a boggy spot so that might help. Otherwise the sprinkler will have to do the job.