An annual workshop offered by the Georgia Botanical Society is called “Aster, Asters, Asters” and it provides hands on learning about members of the Asteraceae family. Look for it every fall on their schedule – I have been twice now and learned just as much the second time. This post, despite having the same name, is about what gardeners call “Asters” – that is, those beautiful fall flowers that look like delicate daisies in the fall but come in shades of white, blue and purple.
|Late purple aster, Symphyotrichum patens|
Aster is a very convenient name, easy to pronounce and easy to remember. That’s why several years ago the taxonomists decided to change all that. Most of the fall blooming North American asters now reside in the genus Symphyotrichum with a few others scattered into other places (like Eurybia). Apparently DNA studies found that North American plants known as Aster were quite different from Eurasian plants known as Aster. Unfortunately Eurasian asters got to keep the old name! You can read more about the change here.
Asters in the genus Symphyotrichum bloom on wiry stems that probably look like weeds to many folks that have not witnessed their transformation in person. The leaves are either rough in texture or small in size - neither attributes designed to win the hearts of gardeners. However, once their blooms open up and reveal those beautiful flowers - every gardener will be wanting to make a place for them!
|Georgia aster, Symphyotrichum georgianum|
Compared to the Georgia aster, late purple aster (Symphyotrichum patens) - shown in the first picture - is slightly smaller, a lighter shade of purple, and has a yellow center. However, the foliage of the two species is very similar; I can't distinguish one from the other unless the plant is blooming.
|Eastern silver aster, Symphyotrichum concolor|
Another blue aster in my area is the eastern silver aster (Symphyotrichum concolor). The habit of this plant is different from the previous ones. Flower buds are closely held against a long stem as are many small leaves. The effect is quite beautiful when the blooms are open.
|Symphyotrichum oblongifolium 'Raydon's Favorite'|
New England aster (Symphyotrichum novae-angliae) is listed as native to Georgia but only sparsely; it is much more common in the mid-Atlantic and New England areas. However it is very showy, with large blue-pink blooms; it has been bred by nurserymen into a popular fall plant with a dense floral display. Aromatic aster (Symphyotrichum oblongifolium) and New York aster (Symphyotrichum novi-belgii), which are not native to Georgia, are also showy. I found the cultivar Symphyotrichum oblongifolium 'Raydon's Favorite' at a plant sale this weekend and people were snapping it up. It was also planted in the venue's gardens where it was doing quite well.
Aren't those blue and purple asters pretty? White asters, however, are the true workhorses of the local aster world. They are the ones popping up in strange places as well as dominating the side of the roads in their season. In fact they are so ubiquitous that people take them for granted. Let's take a few minutes to celebrate their floral awesomeness!
|Calico aster, Symphyotrichum lateriflorum|
I have both of these white asters in my garden, and this week, while taking pictures for this, I discovered a third one that is completely different. Maybe they are mutating!
You can see that the flower arrangement on these two is quite different. A contributing factor is the length of the stem holding the flower. The stem on S. dumosum is long, allowing each flower to stand out as an individual. The stem on S. racemosum is small so that the flowers appear more as a group, each held close to the branch. The flowers are also all facing in the same direction, presenting a very wand-like form (or a raceme, which explains how it got that species name).
Asters in the genus Eurybia have stems and leaves that are different from Symphyotrichum species in terms of shape and texture (that is, stems are not wiry and leaves are smooth, not rough). I suppose that it one reason why the two groups of aster now reside in different genera.
|White wood aster, Eurybia divaricata|
|Showy aster, Eurybia spectabilis|
The other member of this genus in my area is the showy aster, Eurybia spectabilis. The purple blooms are very attractive, and there are often multiple flowers blooming at once. The leaves are quite unlike the white wood aster; they are smooth, dark green and fairly narrow.
If you're looking for some input on asters to choose, I recommend reading this report created by the Mt. Cuba Center based on their garden trials.