Yes I have found a similar thing in my garden in Zone 7 in the Mid-Atlantic. I planted irises after they were finished blooming in my area. Now one of the plants is blooming. I think it has something to do with the cooler than normal August and plants might be fooled. It's been about 10 degrees cooler than usual. You wouldn't think 10 degrees would do it, but who knows. The only thing I'm concerned about is the plant having enough strength to bloom again in the spring! Think I'll give it an added dose of fertilizer later this month. I've been gardening for a long time, but never have had this experience before.

We commonly have this happen after a long hot dry period when many plants go dormant and drop leaves in summer. If a good rain comes or a cool down many trees and shrubs will go into spring mode and bloom. Its a kind of false spring and I believe the plant is confused or its just a natural reaction of coming out of dormancy. It happened often throughout the drought we are now coming out of. I haven't seen it this year but we are still hovering around 99 and 100 degrees.

Our cooler summer is sort of a mirror image false spring to your post-hot/dry season false spring I guess TR10 :-). It's not uncommon to see the magnolias here produce some flowers during a warm spell in late October and early November. I'm surprised though that the pleasantly cool temperatures in part of August was enough to set the viburnum, in particular, back to spring mode. The Blue Riding Hood penstemon that Rouge gave me last summer was also re-blooming last week. Does anyone know if that is its normal pattern? I don't grow any other penstemons, other than Husker Red, and I've not noticed those re-booming.

Funny you mention this 'woody' as I have been pleased with the very vigorous rebloom of a couple of my astrantia. Here is one of them as of today. (First bloomed in June).

In my garden delphinium usually sends up a second spike after the old ones are cut back to the base. Nice late summer blooms.

Last winter weigela 'Polka' was severely eaten back to the snow line at three feet and looked terrible this spring with no bloom. I shaped it and was pleased to see good growth but surprised to see some pink blooms last week. This late bloom has not occurred for me other years.

Rouge, your astrantia looks beautiful. Any secrets for the vigorous bloom?

Rouge

If that's an Astrantia 'Roma', (looks like it). It blooms continuously until frost with deadheading. Started doing that in the second year. My best ever Astrantia as far as blooming.

Astrantia Venice is reblooming as well, not as floriferous.

*Beating drum for 'Roma'*

Thank you mnwsgal.

Thanks for the info boday.

I bet I have 6 Astrantia plants and these are the only two to rebloom. Does that make sense that maybe only "Roma" is able to do this?

I've been extolling the virtues of 'Roma' for a number of years, and yes I've had any number of Astrantias, mostly darker ones such as 'Ruby Wedding' over the years and only 'Roma' has bloomed all season. As I mentioned 'Venus' is reblooming but is very sparse by comparison.

'Roma' is such an subtle plant that people tend to walk right on by it. For example I had it fronted by 'Heart Attack', blooming at the same time and nobody saw the Astrantia until I pointed it out. Everyone was agog about the Dianthus and I was over in the 'Roma' corner going "Hey what about me"?

Here is 'Roma' with 'Heart Attack' towards the end of June. Great idea, didn't work.

Phlox Blue Paradise getting its second wind:

{{gwi:271168}}

Now technically this isnt a rebloom as I planted this columbine early in June 2014 but I noticed just this weekend that it is in bloom for the first time while the foliage is dying as Autumn approaches. Kind of cool.

This epimedium bloomed just fine in the spring and now again it is spitting a few more flowers.

Saw a white primrose blooming today--it's still in its pot and apparently confused!

Love that Heart Attack!

UPDATE:

boday, whatever Astrantia I show above (you think it is "Roma"), it is a bloom machine. It continues to hold it flowers even now. Dare I say it looks just as floriferous now as it did in early summer.

Here is one of our "Indian Pink" in rebloom into October.

auriculas (and the common primula vulgaris) have been having another go-round. An unexpected bonus (I love the fragrance too).