What makes rose bushes bloom twice in the same year? The odd time that it happens I mean.

It is bred into the plant genetically. And not just for roses…some newer species of iris will blood twice, some roses are everblooming, some have a burst for a week and then rebloom with less vigor.

Many flowering plants can be encouraged to rebloom by pruning back after the first flowering (veronica, sage, some clematis…there are long lists in good gardening books).

My forsythia and myrtle will bloom at the end of the summer as well as the beginning if we have a very warm patch.

I have a very fragrant rose called “Thérèse Bugnet.” It blossomed like mad in June..now I have an occasional flower.
Here’s a list of some gorgeous reblooming roses. I grow several of these that can handle the winters of zone 4B.

http://www.squidoo.com/top-10-reblooming-roses

@gailcalled thank you. She said she never did anything different from the past, that is why she finds it a curious thing. Anyway I am sure she will find your info very helpful.

As we all know, gardening is a mysterious art. I never can predict, from year to year, what will happen. Flowers mysteriously appear, disappear and reappear, often in places I never planted them.

For example, I have this year a rainbow of phlox ranging from white to magenta in subtle gradations and no thanks to me.

Our knockout roses bloom from early May until Thanksgiving, even if it’s in the 40’s.

Is that a species name? “Knockout”? Or are you talking about the effect they have on everyone. What zone do you live in?

Knockout is the name of the rose; they come in several colors. I’m in zone 6. They were created at the University of Wisconsin, and are supposed to be good in zones 4 and 5 as well. They’re really easy to care for, I just prune the bush in late March, and deadhead the roses. There a small periods when there aren’t as many blooms, but then it comes roaring back.

@BarnacleBill: I do remember now. I have drooled over them in catalogs; unfortunately they are winter hardy only to zone 5. When I think of what I have spent on perennials and shrubs that were allegedly zone 4; it would have been easier to have skipped the middleman and simply planted the money.

All those David Austen stunners, for example, all those deep holes, all that compost and manure. My sister lives four miles away but has a garden that is fenced and protected from the wind. Her New Dawn is practically devouring her house; mine lasted one season.

Some of the old fashion roses that normally bloom only once, will ocassionally bloom a second time latter in the year.

I have climbing roses in my yard – some people think they are terrible because they spread like weeds – and they bloom all year long.