A white bluebird

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A leucistic bluebird (female?) with a normally colored male.

Today the garden had an unusal visitor who will, perhaps, be a temporary resident: a white eastern bluebird (Sialia sialis). Technically, I suppose she is leucistic, because she retains some faint, diluted color, and her eyes and beak are pigmented.  A true albino would have completely white feathers and pink eyes.

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I assume she is a female, because she was with a normally colored male who was busily stuffing pine needles into the nest box.  I’m a little surprised, not only by the white bluebird, but also that a new pair is moving in.  There was another pair nesting in that box earlier in the spring, and just before Easter, I saw a clutch of eggs when I quickly looked in.  I suppose the young might have left the nest in the last few days, but if so, this new pair have moved very quickly.  Actually, I suppose this could be the same male, with a new lady friend.  The previous female was normally colored, but I can’t tell the males apart.

If this pair produces a clutch, it will be interesting to see if any of the fledglings are leucistic.  Perhaps not, if the trait is recessive, unless the male is also a carrier.

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My favorite orchid

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Encyclia cordigera var. rosea (center) surrounded by the white-lipped semi-alba form of the same species (left), Encyclia randii (top right) and Encyclia profusa (bottom right)

In the twenty-four years that I have been growing orchids, I have bloomed several hundred species and have seen thousands more at orchid society meetings and shows.  Of them all, my favorite is Encyclia cordigera var. rosea.  I love everything about this plant:  the rich purple color of its flowers, the fragrance they produce only when the sun shines directly on them, the predatory appearance of the hooked sepals, the glossy pseudobulbs that can be as large or larger than a goose’s egg, and the leathery leaves that arch above.

There are three color varieties of E. cordigera in nature and in cultivation, all of them worth growing.  Encyclia cordigera var. rosea is the most common variety in cultivation, and in my opinion is the best.  My favorite clone is typical of line-bred specimens that have been selected for rich color and a flat lip. The fragrance of this plant is just wonderful.  It reminds me of hybrid tea roses.:

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Encyclia cordigera var. rosea. A clone that is typical of plants available from orchid nurseries.

I also have a second clone of E. cordigera var. rosea with a slightly paler lip whose edges curve down, but the flowers are at least a third larger than the first clone.  This one came labeled as E. cordigera ‘Rubynz,’ but I have not been able to discover anything about the origin of that clonal name.

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Encyclia cordigera ‘Rubynz.’ It’s flowers are larger than any other Encyclia that I have seen.

The second form of E. cordigera has pigmented sepals and petals and a white lip with a single spot of magenta near the center.  My clone of this color form has a sweeter fragrance, more like candy than roses, with a hint of talcum powder.

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The white-lipped form of Encyclia cordigera

This color form is sometimes erroneously labeled E. cordigera var. randii because of its similarity to a Brazilian species named Encyclia randii.  But although they have a superficially similar color scheme, these are very different species, both in vegetative appearance and cultural requirements.

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The true Encyclia randii from Brazil. E. cordigera can been seen out-of-focus in the background at right.

The third form, Encyclia cordigera forma leucantha has flowers that lack all red pigment, resulting in a white lip with green sepals and petals.  In my clone of this form, the talcum powder smell is stronger, although the fragrance is still pleasant.  The inflorescences are much shorter than those of the other two forms, so the flowers sit just above the leaves instead of arching well above them.  I’m not sure if that is a characteristic of all E. cordigera f. leucantha or just my clone.

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Encyclia cordigera forma leucantha

Ruben Sauleda and Pablo Esperon have recently argued that the E. cordigera with magenta-spotted white lip should be considered a separate species, Encyclia macrochila, based on its distinct color and the different appearance of its hybrids compared to those of E. cordigera var. rosea [1].  They do not mention E. cordigera f. leucantha, so it is not clear whether it would remain E. cordigera or become a form of E. macrochila.  In any case, it remains to be seen whether this interpretation becomes more widely accepted by botanists.  I’m not rushing to change my plant tags yet.

E. cordigera  (including E. macrochila) is native to seasonally dry lowland forest from Mexico to northern South America, so it likes to be grown warm and bright in a mix that dries fairly rapidly after watering.  I use chunks of scoria (red lava rock) in clay pots.  My plants are grown in the half of the greenhouse that isn’t covered by shade cloth, so the sunlight is diffused only by the 8 mm twinwall polycarbonate (and accumulated dirt).  In the summer, they go outside under 30% shade cloth.

The plants have a very predictable growth schedule.  They initiate new growth in late spring, and by autumn the new pseudobulbs are mature.  The plant then sits dormant for a couple of months, but I can usually see the inflorescences starting to grow by late January.  In my greenhouse, E. cordigera f. leucantha blooms first, with the flowers opening in early to mid March.  About three weeks later, the white lipped form blooms, followed by var. rosea in mid April.  Individual flowers last about six weeks, so the bloom times of three forms overlap, and I often have plants in bloom through the end of May.

The previous year’s pseudobulbs also grow roots in the spring, before the growth cycle starts over again, so repotting is best accomplished in late winter.  Unlike many epiphytic orchids which root on new growth, E. cordigera is not a species that you want to repot when the new pseudobulbs are growing. If you damage the roots by repotting in late spring, the plant will have to sit almost a year before it grows enough roots to recover.

With that one caveat though, E. cordigera is a generally easy species to grow and will reward even minimal effort.  It’s definitely one of my retirement home plants–that is, plants I’ll grow when I am old and decrepit and can only take a few favorites with me to the retirement home.

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Encyclia cordigera var. rosea backlit by the sun

Reference

Sauleda RP and Esperon P (2016) The proper name for a central and South American species of Encyclia Hooker.  New World Orchid Nomenclatural Notes 20:1-10.  Link

A tale of two buckeyes

When is a native plant not a native?  It might seem like an absurd question, but as more gardeners try to help wildlife by planting native species and more nurseries cater to them by selling “native” plants, I think it is a question worth considering.  Nurseries often apply the “native” label to any plant from North America, but sometimes it may be important to be more precise.  Two of my favorite small spring-flowering trees, the painted buckeye (Aesculus sylvatica) and red buckeye (Aesculus pavia) illustrate the point.

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Red buckeye (Aesculus pavia) flowering in my garden this week

The genus Aesculus includes a number of large trees such as  A. hippocastanum,  the European horse chestnut (conkers, anyone?), and A. flava, the yellow buckeye.  A. sylvatica and A. pavia are built on a much smaller scale and make great understory trees for shade gardens.  A large garden is not required.  After nine years in the ground, my A. pavia tree is only about eight feet tall, and A. sylvatica often can’t decide if it wants to be a tree or a shrub.

A. pavia has tubular red flowers, clearly an adaptation for pollination by ruby-throated hummingbirds on their spring migration up the east coast.

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Aesculus pavia flowers. A hummingbird’s delight.

A. sylvatica flowers–while they are virtually identical in shape–are yellow and have a smaller volume of more concentrated nectar, the better to attract bees [1].

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Aesculus sylvatica buds and flowers flowers are greenish yellow as they open
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Mature Aesculus sylvatica flowers are yellow with a few streaks of orange

A. sylvatica is a plant of the southeastern piedmont, ranging from southern Virginia to northern Georgia and Alabama.  Here in our part of the piedmont, it is  one of the first trees to leaf out in spring, and on moist, shaded slopes above streams and rivers,  its bright green leaves add a splash of color to woods that are still brown.

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Small Aesculus sylvatica trees (green foliage) next to a little creek near our house in late March.

The A. sylvatica trees in my garden grew from seeds that I collected in the woods adjacent to our property.  It doesn’t get much more native than that.

A. pavia, while it is also native to North Carolina, is a plant of the coastal plain.  The range of the two species in NC seems to overlap only in four counties in the south central part of the state:  Chatham, Lee, Harnett, and Cumberland Counties [2].  This overlap suggests that A. pavia‘s range has extended inland along the Cape Fear River.

Although the two species are clearly distinct, they hybridize readily in cultivation.   It would seem that hummingbirds sometimes visit yellow A. sylvatica flowers and/or bees visit the red A. pavia.  I (and the squirrels) have planted seed produced by the trees in my garden, and the first of the second-generation trees to bloom has bicolored red and yellow flowers, suggesting it is just such a hybrid.

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A probable hybrid buckeye (A. pavia x A. sylvatica) grown from seed produced by my Aesculus pavia tree.

So this creates a dilemma for piedmont gardeners who purchase A. pavia as a “native” tree.  By cultivating red buckeyes within the natural range of A. sylvatica, we have the potential to alter the gene pool of the true natives.  Perhaps a truly conscientious native plant grower should only cultivate A. sylvatica in the piedmont.

But I’m not yet ready to cut down my red buckeye for three reasons.

First, I’m not a very conscientious native plant grower.  While I try to avoid potentially invasive species and want my garden to be wildlife friendly, I grow lots of Asian, African, and South American plants that interest me.  For instance, I grow Aristolochia fimbriata, native to Brazil, rather than the native pipevines simply because I like it better and it functions just as well as a host plant for swallowtail butterflies.

Second, judging by the number of A. pavia trees that I see growing locally, in private gardens, public botanical gardens, and arboretums, this ship has already sailed.  If cultivated A. pavia interfere with the genetics of A. sylvatica, removing my little tree won’t have any significant effect.

Third, the same thing happens naturally.  In northern Georgia, an extensive hybrid zone has been identified where naturally occuring hybrids grow.  This hybrid zone overlaps the natural range of A. sylvatica but not A. pavia, suggesting that migrating hummingbirds carry A. pavia pollen from the coastal plain to the piedmont [3].  I would bet a bucket of buckeyes that there is also natural  gene flow from A. pavia to A. sylvatica in North Carolina.

References

  1.  Burke, JM, Wyatt, R., dePamphilis, CW, Arnold, CW. (2000).  Nectar characteristics of interspecific hybrids in Aesculus (Hippcastanaceae) and Iris (Iridaceae).  Journal of the Torrey Botanical Society 127: 200-206
  2. Radford, AE, Ahles, HF, Bell, CR. (1968).  Manual of the Vascular Flora of the Carolinas, University of North Carolina Press, Chapel Hill.
  3. Modliszewski, JL, Thomas, DL, Fan, C, Crawford, DJ, dePamphils, CW, Xiang, Q-Y (2006).  Ancestral chloroplast polymorphism and historical secondary contact in a broad hybrid zone of Aesculus (Sapindaceae).  American Journal of Botany 93:377-388.

The easiest orchid?

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Bletilla striata. Typical pink flowered form.

People who don’t grow orchids often consider them to be difficult.  People who do grow orchids sometimes feel the same way about terrestrial orchids, particularly hardy species.  Your average orchid grower is perfectly happy messing around with ultrasonic humidifiers, high tech fertilizers, and complex potting mixes containing exotic and expensive materials, both organic and inorganic, in an attempt to grow a delicate little epiphyte from Borneo or the Peruvian cloud forest.  But give them an orchid that grows in the ground outside, and they are at a loss.

Bletilla striata, the Chinese ground orchid, is one species that defies the expectations of both orchid growers and those who just admire orchids from afar.  It’s a terrestrial orchid that is very easy to grow, and given a modicum of care it will steadily increase in size until you have a huge clump to impress your friends.  If you can grow a daffodil, you can probably grow Bletilla.

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My five-year old clump of Bletilla striata grown from a single pseudobulb in a 3-inch pot.  It probably clashes with the red  Aquilegia canadensis and lavendar Iris tectorum that grow all around it, but no one ever accused me of having good color sense.

According to IOSPE, Bletilla striata is native to China, Korea, and Japan (people in the latter nation might have something to say about calling it the Chinese ground orchid).  I’m not sure where in its fairly wide native range the plants in cultivation originate, but they are certainly cold hardy. My plant has easily survived 5 F (-15 C), and the species is reported to be hardy in USDA Zone 5 (-10 to -20 F, -23 to -29 C winter minimum) with protection.  My plant is growing in my standard mix of native clay and permatill, top-dressed with hardwood mulch, but any reasonably well-drained, slightly acidic garden soil would probably be fine.  Morning sun and some afternoon shade will provide sufficient light for flowering without scorching the leaves.

The flowers are relatively short-lived and don’t have the greatest form, but the buds open successively for several weeks.  In addition to the standard pink form, there are alba (white-flowered) and coerulea (“blue”) forms.  Several clones with variegated leaves are also widely distributed.  This spring, I obtained several pseudobulbs of an alba clone at a very reasonable price from one of the big bulb vendors.  I’ll be interested to see if it grows as easily as the typical form.

If Bletilla striata has a flaw, it is its eagerness to grow in early spring, at least in our mild climate.  The pseudobulbs are fairly close to the soil surface, so they warm up quickly and often initiate new growth in February, long before the last freezing weather.  Although dormant plants are very cold hardy, the new leaves, and especially the flower buds which emerge simultaneously with the leaves, are very sensitive to frost.  Leaves will continue growing even if the tips freeze, but frozen buds mean no flowers until next year.

This past winter, we had very warm weather in February, and new growth was well under way when a low of 25 F (-4 C) was forecast.  In an effort to save inflorescences that were already starting to emerge, I covered the entire clump with a black plastic cement mixing tub and several inches of mulch.  I keep several of these sturdy tubs around to serve as water reservoirs for potted bog plants, and they are also very useful for covering tender plants.  After several days, I removed the tub so that the new growth wouldn’t rot in the humid darkness and then replaced it again when more freezing weather was forecast.  The procedure was labor intensive but worked perfectly, and this year’s display of flowers is probably the best yet.

Calanthe update

In my post about Calanthe sieboldii, I mentioned that the hybrid Calanthe Takane was in bud.  The flowers are now open, and I am quite pleased.  C. Takane is a cross of C. sieboldii and the much smaller and less colorful, but hardier, C. discolor.  My C. Takane shows its parentage in the yellow lip (from C. sieboldii) and reddish brown sepals and petals (from C. discolor).  It is intermediate in size between its two parents.  Take a look:

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Calanthe Takane (C. discolor x C. sieboldii)

Flowers of the west wind

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Zephyranthes atamasco flowering in my garden.

Now is the season for Atamasco lily, Zephyranthes atamasco, to bloom in the central NC piedmont.  The thin, grassy leaves are often lost among true grasses, so the surprisingly large flowers (~8 or 9 cm wide) seem to appear from nowhere.  Z. atamasco likes wet soil while in growth and can be found in moist deciduous woods, roadside ditches, and boggy meadows. In the woods, the plants produce their foliage while the trees are bare and bloom just as the canopy fills in, but they flower best in the open where they get  more light.  The plants below are in a meadow that I frequently drive past.

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They’re on private land, so I stood on the road and took pictures with a telephoto lens this afternoon.

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Once upon a time, Zephyranthes atamasco was a common lawn flower, but more frequent mowing and the use of herbicides to control weeds has reduced its frequency.  In our neighborhood, there’s one house with a lawn that isn’t mowed often.  Currently, it is snowy white with the flowers of bluets (Houstonia caerulea) and atamasco lilies.  It’s quite a sight.  Elsewhere in the neighborhood, plants bloom in the long grass at the side of the road:

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In nature, Z. atamasco grows in the coastal plain and piedmont from extreme southeastern Maryland and Virginia, south to northern Florida and west to Mississippi.  It could almost certainly be grown north and west of its natural range if the bulbs are protected from freezing.

Z. atamasco can be be obtained from various native plant nurseries, and seed is sometimes available from the North Carolina Botanical Garden Seed Program.  In the garden, Z. atamasco  produces new leaves in late winter and wants plenty of water while growing.  It will go dormant if the soil dries out in the heat of summer but grows best with consistent moisture.  A couple of plants that I grow in large pots sitting in a tray of water retain their leaves much longer than the plants in the ground, and they occasionally flower again in autumn.

Other Zephyranthes species are found from the Southern U.S. through central and South America as far south as Argentina.  Together with their close relatives in the genus Habranthus, the tropical and subtropical Zephyranthes are collectively known as rain lilies, because they bloom intermittently, usually after a thunderstorm.  A wide range of species and hybrids are hardy in zone 7 and may actually be easier than Z. atamasco to grow in regular garden soil.  In my garden, I grow Zephyranthes grandiflora (pink flowers, Mexico and central America), Z. flavissima (yellow, southern Brazil to Argentina), Z. candida (white, Argentina and Uruguay), Z. smallii (yellow, Texas), and Habranthus tubispathus var. texensis (orange, Texas).

For further details on rain lilies, see the very informative wiki of the Pacific Bulb society.