[ Lost in the Landscape ]

fun with hybrids

There are over a quar­ter mil­lion plant species known to biol­ogy. Of those more than 5,000 can be found in Cal­i­for­nia, and 1,500 in San Diego County alone. With so many amaz­ing plant species out there I still find myself being inter­est­ing in hybrids between the pure species.

My last post was on Sar­race­nia, the North Amer­i­can pitcher plants. The genus appears to be fairly new to the world in evo­lu­tion­ary terms, and all the species in the genus will hybridize eas­ily with any of the oth­ers. And all these hybrids will con­tinue to inter­breed with the par­ent species or other hybrids. When you find a bog with two or more species in it, chances are good that you’ll find inter­me­di­ate plants with traits of all the species present in that location.

This dri­ves biol­o­gists crazy. Find­ing a plant that’s a pure species can be a major headache when the plants are out there, frol­ick­ing in the mud. But evo­lu­tion­ary biol­ogy acknowl­edges that hybrids can intro­duce new genes into a plant’s gene pool so that they might be bet­ter equipped to with­stand some stres­sors that a pure species might not.

In addi­tion to pos­si­ble evo­lu­tion­ary advan­tages, a hybrid plant found in nature can be a really cool-looking mon­grel. And human-created hybrids that have been selected for spe­cific traits over gen­er­a­tions can begin to take a species or genus in direc­tions nature would never have imagined.

Here on the left is the Sar­race­nia hybrid Judith Hin­dle. I first encoun­tered mass tissue-cultured num­bers of it in the flower aisle at Trader Joe’s a cou­ple years ago. It’s a pretty great-looking plant by itself, but imag­ine a whole store dis­play of it. This human cre­ated selec­tion derives from three species, and its pedi­gree can be notated: ((Sar­race­nia pur­purea x S. flava) x S. leu­co­phylla) x ((S. pur­purea x S. flava) x S. leu­co­phylla).

Doing the math, you an see that it’s one-fourth S. pur­purea, this species. (My photo here isn’t the exact par­ent, just one gen­eral exam­ple of what this vari­able species can look like. Sev­eral tax­on­o­mists have decided that this plant I’ve shown you, S. pur­purea var. burkii, is actu­ally a new species, S. rosea, but it looks quite sim­i­lar and you can get the gen­eral idea…)

Another quar­ter of the ances­try comes from S. flava. (You might rec­og­nize this same photo from my last post. Once again this is just a rough esti­ma­tion of what the par­ent looked like. It’s actual great-grandparents were S. flava var. rugelli, a plant with pure green pitch­ers with a red patch in the throat.)

And the final two quar­ters of its ances­try comes from the gor­geous S. leu­co­phylla, the white-topped pitcher plant. I find myself com­par­ing the hybrid with the par­ents, try­ing to see the char­ac­ter­is­tics that came through in the final hybrid. Clearly S. leu­co­phylla has the most influ­ence in this cross.

Here’s another com­mon sar­race­nia, S. Dixie Lace. Larry Mel­lichamp, its breeder, isn’t 100% cer­tain of its parent­age, but he esti­mates it to be: (S. leu­co­phylla x S. rubra) x (S. psittacina x S. pur­purea). It shares two par­ents with Judith Hin­dle above, but intro­duces two new species into the mix.

The pres­ence of this ances­tor, S. rubra, is sub­tle, and is prob­a­bly most man­i­fested in the some­what upright-growing pitch­ers and the robust growth habit. (Once again, the plant I’ve shown is only a close approx­i­ma­tion of the S. rubra var. wher­ryi that was used for the actual cross. And yet again, this lat­ter species has been clas­si­fied as a sep­a­rate species by some taxonomists.)

The final ances­tor is S. psittacina, a plant that’s prac­ti­cally impos­si­ble to hide the pres­ence of in any hybrid. The lean­ing growth habit and pat­tern­ing of the pitch­ers takes sev­eral gen­er­a­tions to fade into the background.

Hybrids can hap­pen any­where. In the irri­gated part of my gar­den I have a few sage species from Europe and the Amer­i­cas. These are the leaves of Salvia sagit­tata, the arrow-leaved sage, a plant from Ecuador.

Next to it I noticed a young plant which at first I thought was a seedling of the of its neigh­bor. It has the same light green col­oration and coarse leaf tex­ture as does S. sagit­tata. When I started look­ing closer at the leaves, how­ever, some­thing seemed a lit­tle off. Instead of the dis­tinct arrow shape, the leaves are closer to oval. Seedlings some­times take a while to develop their mature char­ac­ter­is­tics, but I started think­ing that it might be a hybrid of S. sagit­tata with one of the other sages nearby.

Three feet away is S. nemorosa. It also has coarse-textured leaves, but they’re smaller, darker green and rounder (prob­a­bly “lin­ear” to “oblong” with a “cor­date” leaf base, accord­ing to the leaf mor­phol­ogy charts).

And about six feet away are sev­eral plants of the pop­u­lar ‘Hot Lips’ cul­ti­var of S. micro­phylla, a species from Texas into Mex­ico. Its leaves are smooth, much smaller, darker green and also more rounded. (I guess I’d call it an “ovate” leaf form with an “obtuse” leaf tip.)

Who do you think might be the father? I’m lean­ing towards S. nemorosa.

The seedling sage found a clear­ing in the mid­dle of a lit­tle walk­way to ger­mi­nate. I’ll let the seedling bloom to see if it’s interesting–or if it’s even a hybrid at all. See­ing the flow­ers should help me bet­ter guess what its par­ents might be. If it’s worth keep­ing I’ll trans­plant it out of harm’s way. If it’s not, I’ll treat it as any other unwanted gar­den col­o­nizer. What­ever the case, it’ll be an inter­est­ing lit­tle experiment.

Topic for a future post: What’s bad about hybrids?

October 27 2009 | Categories: gardening • my garden | Tags: hybrids • sages • Salvia microphylla 'Hot Lips' • Salvia nemorosa • Salvia sagittata • sarracenia • Sarracenia flava • Sarracenia leucophylla • Sarracenia psittacina • Sarracenia purpurea • Sarracenia rubra | 4 Comments »

true blue sages

There are plenty of names for shades of blue: azure, cerulean, indigo, cobalt, ultra­ma­rine, sky, and navy. And then there’s even the spe­cial syn­thetic intense ultra­ma­rine shade that artist Yves Klein patented under the name “Inter­na­tional Klein blue.”

A visit to a nurs­ery, how­ever, seems to come up with only a short list of plants hav­ing flow­ers that are truly, intensely blue. Among the more com­mon plants pan­sies, del­phini­ums, peri­win­kles and corn­flow­ers would qual­ify. But decades of breed­ing attempts with roses and pha­laenop­sis and cat­t­leya orchids have failed to pro­duced any­thing other than pale mau­vey or laven­derey col­ors, mainly because those plants don’t pro­duce the nec­es­sary blue pig­ments in the first place.

There are lab­o­ra­tory sub­jects that have been genet­i­cally mod­i­fied to carry the genes to pro­duce blue pig­ment, and they’re pro­duc­ing flow­ers that are knock­ing on the door of being blue. For a flower to be blue, how­ever, in addi­tion to hav­ing the right pig­ments, the pH of the petals has to be absolutely cor­rect. Oth­er­wise you get pinks or more of those close-but-no-cigar col­ors like lilac. (If you’ve played with alter­ing the color of hydrangea blos­soms or mak­ing lit­mus paper change from pink to blue you’re already famil­iar with the con­trol­ling effects of acid­ity. Of course the big dif­fer­ence is that you can accom­plish hydrangea color change with­out going into the lab.) The basic genetic mod­i­fi­ca­tion process creeps me out a bit, and genetically-modified car­na­tions are sen­si­bly banned from Europe.

For­tu­nately the sage genus, Salvia, con­tains a num­ber of species with flow­ers that require no genetic manip­u­la­tion to achieve their amaz­ingly blue col­ors. I’ve devoted a cor­ner of my gar­den to three of them: ivy-leafed sage, arrow-leafed sage, and gen­tian sage.

The three species com­pared, left to right: Salvia patens ‘Oceano Blue,’ S. cacali­ae­fo­lia, and S. sagit­tata.

The ivy-leafed sage, Salvia cacali­ae­fo­lia, is a robust grower, four to five feet tall and as big around as you’ll let it get. I’m start­ing to call it the “walk­ing sage” because it can set down roots where the fairly lax stems touch the ground. It also sends up new stems from run­ners, though these don’t wan­der too far from the plant. Ram­bunc­tious, yes, but the plant has been eas­ily con­trolled with the help of Mis­ter Prun­ing Shears.

As its com­mon name would sug­gest the leaves are a lit­tle ivy-like, tri­an­gu­lar, three inches in length, and a pleas­ant medium green color. The spaces between the paired leaves can approach eight or nine inches, mak­ing the plant look a lit­tle stemmy and infor­mal, but I find the mound­ing plant to be grace­ful and attractive.

Before the flow­ers open the buds develop an intense, almost indigo-blue shade, about as close to Inter­na­tional Klein Blue as you’ll find in the gar­den. The buds open to clean blue flow­ers, fairly sim­ple tubu­lar affairs that are about and inch and a quar­ter long. What the flow­ers might lack in size and showy com­plex­ity they make up with their sheer pro­fu­sion. The plant went into the ground Novem­ber 18 of last year, and it’s never been with­out flow­ers except for when the sprin­kler or heavy rains knocked them off. Har­di­ness reported to Zone 9.

The arrow-leafed sage, Salvia sagit­tata, grows smaller than the pre­vi­ous species. So far, for me, the plant is maybe two feet tall and three wide, with the inflo­res­cence adding a foot to the height. True to name, the leaves are shaped like an arrow­head. They eas­ily attain six inches in length, and have an attrac­tive light, almost lime-green col­oration. Towards the end of the sea­son the plant can lose its lower leaves and get leggy, so you might want to plant some­thing small and mound­ing near the plant to dis­guise the stems. (I’ve planted some lime thyme.)

The flow­ers are about the same size as those of the ivy-leaved sage, and take the form of small tubes with one petal mod­i­fied to form a frilly lit­tle “skirt”–a handy plat­form for insects to land on. (If this were an orchid, the flower part would be called the label­lum, the “lip.”) The blooms float on thin, dark stems that make them look like exotic lit­tle but­ter­flies hov­er­ing over the plant. Their color is a vivid medium blue color, a main-line blue so pure it doesn’t need a fancy name. Peak bloom runs from May to late fall in San Diego. Con­sid­ered a ten­der peren­nial, prob­a­bly hardy into Zone 9.

The gen­tian sage, Salvia patens, is the newest addi­tion to my gar­den. The clone I chose is ‘Oceano Blue.’ So far the plant is about 30 inches tall and 15 wide, def­i­nitely the most con­strained of these three species. Leaves are oval-to-pointed (“ovate”), medium-dark green, and about two inches long.

The flow­ers are almost iden­ti­cal to arrow-leaved sage in color–an intense medium blue–but the flow­ers are huge by con­trast, exceed­ing two inches in length and height. The petals have a dis­tinct for­ma­tion that makes me think of a crab claw. I haven’t grown it through the warmest months, but it has a rep­u­ta­tion for slow­ing down in its florif­er­ous­ness, some­thing I’m begin­ning to observe. Har­di­ness reported to Zone 8.

And what about the com­mon bed­ding plant Salvia fari­nacea ‘Vic­to­ria Blue,’ the mealy cup sage? It can be a great plant, par­tic­u­larly in warmer, less humid cli­mates and sea­sons when pow­dery mildew isn’t an issue. The flow­ers, how­ever, range more towards blue-violet, not a pure shade of blue. So if you’re a blue purist, fuggedaboutit.

June 21 2008 | Categories: my garden • plant profiles | Tags: arrow-leaved sage • blue • blue flowers • gentian sage • ivy-leaved sage • mealy cup sage • sage • sages • Salvia cacaliaefolia • Salvia farinacea • Salvia patens • Salvia sagittata • salvias | No Comments »