Friday, September 23, 2011

Fall Color Explained.

Leaves from the CA Native Vine Maple (Acer circinatum)

Being a Californian, I experience what people from other parts of the country call "Fall Lite". Oh yes, these people make fun of us and our lack of "real" seasons but their poorly masked envy of our mild Mediterranean paradise (and all kinds of awesome at arm's length) doesn't phase me one bit. Besides, I've learned to grab my share of fall color and get it every place I can.... from the big leaf maple lined creeks of Skyline, to the dogwoods and poplars of the sierras to the wide spectrum of garden and street trees that show off all hues from that fiery warm slice of the color wheel.

Chinese Pistache: a common Bay Area street tree.
Despite our mild version of the season, Autumn is still my favorite time of year. I soak up the changing colors with an intense joy like welcoming an old dear friend who comes around each year to usher in a time of lovely memories, scents, sounds, tastes and adventures. Like mom's minestrone wafting down the hall to a hot cup of tea by the fire with a good book, the changing of the leaves marks a sweet shift from the go-go crazy fun of summer to harvest, reflection and introspection.

So what makes leaves change color? In order to discuss color, we must first discuss the pigments responsible. Contributing Autumnal pigments from nature's paint palette go as follows:

  • Chlorophyll- the green pigment that rocks photosynthesis (converting light to sugar)
  • Carotenoids- such as xanthophylls or the more familiar carotene, responsible for yellows, oranges, and brown pigments (as seen in as carots, corn, apricots, narcissus, bananas, etc)- and function to absorb light energy for use in photosynthesis
  • Anthocyanins- as the suffix "cyan" suggests, is the red and purple pigment that gives it's color to apples, berries, grapes, cherries, violas, cabbage, etc. They are water soluble and appear in the watery liquid of leaf cells.

Both chlorophyll and carotenoids are present in the leaves throughout the growing season. But most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells as a means of photprotection during nitrogen translocation (or as I look at it: a kind of natural sunscreen while the plant relocating nutrients away from the leaves for storage and food).

In a nutshell, Fall color happens due to two factors: 1.) the breakdown of green chlorophyll (in response to shorter days), which unmasks the already-present orange and yellow pigments (carotenoids) while 2.) the red is from a simultaneous process going on which I mentioned above with the anthocyanins being produced in response to light.

Why are some years so much better for Fall color than others? 
Lagerstroemia (Crepe Myrtle)
It all has to do with temperature & weather during the period of season shift (but overall weather of the entire year contributes as well). Warm, sunny days and cool but not freezing nights bring on the most dramatic fall color. Reason: During these warm sunny days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions bring on production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors generally stay consistent. So the variability of the temperature/weather create the different gradations of yellow to red to orange that change from year to year.

Ginkgo Biloba
The endless variables of weather patterns of the year will effect the timing and drama of the fall show, just like it will effect the bloom times and crops. The ideal year for a killer Autumn show is a wet rainy winter & spring, a good "normal" summer and warm sunny fall days with cool nights. Of course, us being in this mild climate we love so dearly, those cool nights are still relatively mild. Therefore no technicolor Fall madness like I've heard tell of on the East Coast. Still we've got quite a bit of lovelies that put on a good "last hurrah to summer" show. Start gazing at street and park trees or plants while hiking through the hills and you'll start to see and admire them like I do. A great one to admire (from afar) is poison oak. It decorates the landscapes of almost all plant communities in California and when in masses, creates a brilliant tapestry of color with the existing landscape.

Poison Oak in Fall
So whether or not we completely understand why the colors are the way they are, we can all sit back in admiration of nature's paint mixing party. And on a larger scale, watching the leaves drop, recycle nutrients and break down into a humusy soil layer- feeding fungi, plants and an entire ecosystem (including many critters invisible to the naked eye) while the woody tissues seal themselves off in protection from the cold... as the seasons cycle. Well it's all pretty awesome to soak in. I dig it. Happy Autumn.

Friday, September 16, 2011

Plant Companions

Greetings fellow plant friends. I was in a client's garden today prepping their beds for winter veggies when I remembered this old resource I thought I'd share regarding plant companions (from Common Ground in Palo Alto). Great stuff. All this this info is also available in John Jeavon's book (How to Grow More Vegetables).

Check out the link below:

Wednesday, September 14, 2011

Who's this Douglas Guy? and what about that Menzies Dude?

Many of you, whom, like me, are into CA native plants and/or identifying flora on bay area hikes may have wondered: who's this Douglas guy? He's got a fir, iris, artemesia and whole slew of other California plant species all to his name. For years I spouted off the words Iris douglasiana without even thinking. But today, well I finally decided to explore further and found the honorable Mr. Douglas of the Douglas Fir (which sidebar: is neither a fir <abies> NOR a hemlock <tsuga> but a psudotsuga- translation "kinda a hemlock"- menzesii- named for a rival botanist, Archibald Menzies, another Scottish dude- I find this humorous that the common name can shout out to one botanist while the botanic name can to the other) is (I'm quoting wikipedia now) David Douglas (25 June 1799 – 12 July 1834), a Scottish botanist. He worked as a gardener, and explored the Scottish Highlands, North America, and Hawaii, where he died. A cool resource for further information: Interesting short article for the name drops of other botanists (Torrey- i.e. Torrey Pine and Nutall- i.e. Cornus nutalli, or native dogwood- he's also got a woodpecker and viola to his name). See below for photo of Mr Douglas.

On top of having a good several dozen native shrubs, sub-shrubs, perennials and bulbs to his name, he also boasts several species of American oaks and pines. Douglas is a mysterious kind of guy. So I'm having issues finding out more about him. But hey. He's another Scottish naturalist, like John Muir (what's with these Scottish naturalists coming to CA?). Although it looks like Mr Muir took over the shift as his reign was from April 1838 –  December 1914.

Okay now I'm going to side bar into a whole other rant. Because I'm wondering- who is this Menzies dude? He's got an herb and hey, even one of CA's coolest trees, the madrone named after him. Well here's what I found. Now if I found out that Douglas and Menzies where friends like Van Gough and Gaughan, well that would be totally awesome. Well I didn't find that, which doesn't mean it isn't true but I did find he lived from 15 March 1754 – 15 February 1842 and was a Scottish surgeon, botanist and naturalist. With a name like Archibald Menzies, he was bound be a rockstar. Dude even has his own genus of shrubs in the ericaceae (the bell shaped flowered family of blueberries, arbutus, erica, etc.) family- Menziesia. The lovely Mr Menzies below.

Bottom line to this rant: all plants have meanings- the cooler ones are of Latin or Greek derivations with awesome myths to boot... the less cool ones have old dead botanists to blame. More so, I hope to have a plant named after me before I die. Is this a self-serving desire? Perhaps. But I see it this way: some people want kids to carry on their name and legacy. Me? I'll take some dogs and an awesome Ribes or Aesculus... perhaps Aesculus californica 'Andrea's Red' or Ribes sanguineum 'Miss Andi's Choice' or maybe even Arctostaphyllos 'Kickass Andi'. Interested botanists can inquire with me for further classifications and questions.

Also, along the vein of plant meanings, etymology and derivations- I challenge you, the reader of these rambling words to play stump the horticulturist. Try me. For ex. Cupressus macrocarpa - Cypress- big seed. Let's play. We'll all learn a little Latin, a little plant geek and have a little fun.

Happy plant geeking.