Showing posts with label coumarin. Show all posts
Showing posts with label coumarin. Show all posts

Tuesday, January 15, 2013

The January Garden - Sweet Woodruff

I have fallen in love with Sweet Woodruff (Galium odoratum, a.k.a. Asperula odorata). Here in the heart of winter, Sweet Woodruff is looking greener, healthier and more beautiful than ever. The winter coloration (purpling) of some leaves just adds to the beauty for me.

UPDATE - As time goes by and I see how a plant performs in the garden from year to year, my views may change and I'll update old posts accordingly. That's what happened with sweet woodruff. I started experiencing dieback on patches of this plant in both winter and summer. One of the readers from South Carolina who left a comment also reported problems with this plant. I suspect it's a bit difficult to grow in the hot and humid Southeast and especially the Deep South. At the same time, when I started to try to dig up patches, I found a disturbingly elaborate web of roots that seemed to occupy the entire top layer of soil. I could literally lift the plant and the soil would come with it like a piece of carpet. So I ended up evicting sweet woodruff entirely from my garden. Fortunately, unlike Ajuga or Geranium sanguineum at least it had the decency to leave politely and not try to make too many repeated comebacks. I've since shifted my gardening more toward natives, especially vis-a-vis spreading groundcovers. If you do grow this plant in the U.S., please check to make sure it's not invasive in your region, as might be the case particularly in the Pacific Northwest, Upper Midwest and parts of New York State.


I guess normal gardeners love roses, daylilies, viburnums, azaleas and rhododendrons.

Me? I fell in love with a groundcover - Sweet Woodruff, Galium odoratum, also known as Asperula odorata.

The Internet is full of interesting information about this plant:

Living in Season notes that in Germany (where the plant is called Waldmeister or "Master of the Woods"), fragrant dried sprigs are used to flavor May Wine. But that killjoy FDA has nixed consumption of Sweet Woodruff due to the fact that the plant contains a chemical called coumarin.

Now I'm neither a lawyer, nor a chemist nor a doctor. (I don't even play any of those roles on TV.) So I'm not going to even attempt to tell you whether or not it's safe, legal or smart to use Sweet Woodruff to flavor your wine. Do your own research. Consult with experts. Make your conclusions.

But it does seem to be perfectly safe (near as I can tell) to dry Sweet Woodruff sprigs and use them for potpourri or air freshener. I haven't tried that yet, but perhaps I will do so this year.

Just another shot of beautiful Sweet Woodruff foliage, which is supposedly fragrant when dried. I like the greens and the purples. I like it all. There is something here that reminds of me of both snowflakes and fractals.

Some folks say that Sweet Woodruff can be aggressive. That has not been my experience (yet) but I can see how eventually it might overtake particularly small or retiring competitors. But Sustainable Gardening (which has a beautiful photo of a whole bed of Sweet Woodruff) notes that the plant is rather delicate and can be easily uprooted, kept in bounds and otherwise controlled. Sustainable Gardening also points out that the low-growing Sweet Woodruff (mine can't be taller than 4-6 inches at most, though some sources insist it can grow up to 12-inches tall) is no threat to bushes, shrubs or tall perennials.

See the little sprout of Sweet Woodruff poking through the soil on the left-hand side of the photo. Sweet Woodruff will spread, but the new plants pop up near the mother plant and I've found the plant easy to control / uproot if necessary. In fact, I wish it would spread faster! (As always, YMMV depending on climate, soil, rainfall, etc.)

Now Mother Earth Living warns that Sweet Woodruff will struggle in the hot and humid South. That hasn't been my experience at all. I planted Sweet Woodruff last spring, just before a long, hot and dry summer. And when I say "hot", I'm talking record heat (110+ degrees Fahrenheit). It's true, I did give this plant partial shade (its natural environment is woodlands after all), but my Sweet Woodruff still got fairly intense sun all morning during the summer in its east-facing foundation bed. That's maybe 6 hours of sun, which would be considered 'full sun' in some books.

And yet, the plant performed like a champ. It didn't grow much, but it didn't wither or croak either. It just kind of hunkered down and stayed green and pretty. A couple of stems might have browned and died, but the overall effect was undiminished. This is a tough cookie. But if I were to do it again, I'd suggest Southern gardeners plant Sweet Woodruff in the fall, since a new plant that I added to the landscape in autumn seems to be getting off to a much better start than the one I threw into the deep end of a long hot Tennessee summer.

Anyway, cooler weather came eventually. Lows in the low-20s recently. Highs sometimes only in the 30s. But Sweet Woodruff is hardy to zone 4. That means it should be able to handle lows in the negative-30 Fahrenheit range. 20 above freezing is just a walk in the park. Which might be why my Sweet Woodruff, which looked fine in July, now looks positively cheerful.

(I should say it looks mostly cheerful. Certain stems do appear dead or damaged, especially on the smaller plants that I divided or planted this autumn. But even those have very healthy-looking new foliage emerging from underground, so I'm fairly confident that they'll be fine come springtime and may even benefit from a haircut.)

Where Sweet Woodruff waited out the summer, it is now growing and expanding in the middle of winter. When I redid the front foundation this summer, I transplanted the Sweet Woodruff a bit closer to the front of the bed, where it would be more visible. At that time, I divided the plant and replanted the offset nearby. And I also planted a new Sweet Woodruff plant that I'd ordered through the mail from Gardens in the Wood of Grassy Creek.

The Sweet Woodruff I bought and planted just a couple of months ago from Gardens in the Wood of Grassy Creek. The 'mama' plant is still pretty small, but look how much she's already spreading to the right with shallow stolons and pretty little rosettes popping up - and this is in heavy clay with a light scattering of mulch on top!

All three plants are doing great now. The one from Gardens in the Wood in particular is expanding and scouting out new territory even though the central clump is still pretty small. And I'm looking forward to hopefully seeing a show of white blossoms that Paghat says should make an appearance in April and May.

So to recap, it's not flashy or showy, but I think Sweet Woodruff deserves to be planted in far more gardens. Here's why:

1. Evergreen (so far, in zone 6/7, during a winter with temps close to average, lows in the 20s, highs in the 30s and 40s)

2. Nicely spreading - clearly desirable in a groundcover - but not overly aggressive.

3. Interesting and beautifully whorled foliage, which can supposedly be cut back to stimulate regrowth. Haven't tried that yet, but will report back when/if I do make that experiment.

4. Flowers (reportedly) in spring that are supposed to attract butterflies and bees, according to Agweek (which agrees with me that Sweet Woodruff is "one of the best groundcovers")

5. Fragrance (reportedly, of dried branches). Also haven't tried this yet, but will report back when/if I do.

6. Suppresses / controls weeds, which makes a gardener's life more carefree and lighthearted!

Do you grow Sweet Woodruff in your garden? If so, please post your experiences in the Comments section below!

Curious to see if my love affair with Sweet Woodruff will last? Want to know whether Sweet Woodruff will flower and if the scent of the dried sprigs really is as good as everyone says? Stay tuned with email updates.