Houston: Mercer Botanical Gardens (Six on Saturday #32)

Mercer Botanical Gardens are located north of downtown Houston, very close to George Bush Intercontinental Airport.  I had visited the gardens once before, about seventeen years ago, but remembered very little, so during our recent trip to Houston, I took the opportunity to renew my acquaintance.

I had forgotten about Hurricane Harvey.  During the flooding last year, the gardens were submerged under eight feet of muddy, polluted water.  Clearly the floods did a lot of damage, and just as clearly the gardens employees and volunteers have been working very hard to repair the damage. This article from the Houston Chronicle describes the devastation, and a google image search will show you what the gardens once were.  These six pictures will give you a little taste of what the gardens are now, and a hint of what they will be again.

1.  Dead palm tree

dead_palm

Some of the garden grounds were still closed off, and in the open areas damaged plants were still visible.  After the flooding, last winter included an unusually prolonged cold spell in the Houston area, which probably did not help the tender palms.  Virtually all of those that were still alive had damaged fronds, but that damage is temporary.  I’m not sure if this palm tree was left in the ground because the staff had been overwhelmed, or if they were waiting to see if it might resprout.

2.  Zephyranthes (rain lilies)

zephyranthes1

Many of the plants that seemed to be in the best conditions were tropical bulbs and rhizomes, particularly those that tolerate wet soil (crinum, gingers, etc).  Presumably, these plants resisted being washed away by the flood, and any top damage was easily replaced.  I saw an enormous clump of Hymenocallis caribaea, unfortunately not blooming, that was in prime condition, but the best flowers were on these unlabeled Zephyranthes.  They were blooming all by themselves in a rock garden area that appeared to have been recently renovated but not yet replanted.

3-5. Tropical shrubs and trees

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Erythrina crista-galli, one of the parents of Erythrina x. bidwillii

Although many of the beds are thus far, still fairly barren, splashes of color from vigrous perennials and fast growing tropical trees and shrubs hint at how spectacular the gardens will be again in a few years.

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Huge, hot-pink flowers of Lagerstroemia speciosa
Stachytarpheta
Stachytarpheta mutabilis (coral porterweed)

6.  Anolis sagrei (brown anole)

Anolis_sagrei

The gardens were swarming with little brown anoles.  A. sagrei is native to Cuba and the Bahamas, and it is an invasive species in the southeastern U.S.  where it often replaces the native Anolis carolinensis (green anole).  My parents’ garden south of Houston still has green anoles, but I didn’t see a single native lizard at Mercer.

So, that’s Six on Saturday and a very brief look at Mercer as it is now.  For more Six on Saturday, head over to the blog of The Propagator, who started this weekly exercise and collects links from other participants.

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Crinum macowanii

With a range extending from South Africa northwards to Eritrea [1], Crinum macowanii is one of the most widespread Crinum species in Africa.  The plants in my collection were bred from specimens originating in Zambia.

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The slightly glaucous leaves of this Zambian form have attractive undulate margins, and although the inflorescence is relatively short, it emerges from the side of the bulb and is not obscured by the foliage.  The flowers are short-lived, like those of most crinums, but powerfully fragrant.  My large bulb produces several inflorescences in succession, usually in June.

Crinum_macowanii1

I planted the bulb about eight inches deep and cover it with several inches of mulch after the foliage freezes off.  That seems to be all the winter protection it needs, even though it is planted in soil that remains quite wet in winter.  The bulb does not seem to offset, but flowers are self-fertile.  Seedlings have grown well, retaining some green leaves through much of the winter in the greenhouse.  My largest seedlings are currently about two years old, and I’d guess they’re about two more years from blooming.

In areas too cold for growing it in the ground, this is probably a reasonable candidate for cultivation in a large pot or tub.  When I purchased my first bulb, it bloomed in an 8-inch diameter pot and survived the winter completely dry, stored in the crawl space.  However,  the leaves have been much larger and inflorescences more numerous since I planted it out in a flower bed.

Crinum_macowanii2

Reference

1. Duncan, G., Jeppe, B., and Voight, L. (2016)  The Amaryllidaceae of Southern Africa, Umdaus Press, Pretoria, South Africa.

First bloom: Crinum bulbispermum

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Crinum bulbispermum ‘Jumbo’

The largest of a batch of seed-grown Crinum bulbispermum ‘Jumbo’ is finally blooming, five years after the seed germinated.  I suspect it would have bloomed earlier if it were growing in more fertile soil, but it was worth the wait.  According to the Pacific Bulb Society Wiki, ‘Jumbo’ is a seed strain developed by the late L.S. Hannibal, who selectively bred C. bulbispermum to obtain plants with larger flowers, better color, and inflorescences that don’t flop.  My seedling has flowers that open with a deep pink flush at the base of the petals and darken as they age until they are almost red.  The 20-inch tall (51 cm) inflorescence remained upright without staking, unlike some of the other crinums I grow.

C. bulbispermum is reputed to be the most cold hardy of the South African crinums, with numerous reports of it surviving in Zones 5/6.  In my garden, most crinum foliage turns to mush at a couple of degrees below freezing, but the 3-foot long (90 cm) leaves of C. bulbispermum survive down to near 20 F (or possibly colder) and start growing again early in spring, long before the other crinums poke their noses above the mulch.

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Ammocharis coranica

Ammocharis_coranica

Ammocharis coranica is a very easy amaryllid to grow.  Its range includes the summer-rainfall and arid Karoo regions of South Africa and extends into Angola and Zimbabwe.  Consonant with such a broad habitat, it seems to be opportunistic, producing new growth whenever water is available, regardless of the season.  If watered year-round, it will remain evergreen, but it will bloom most reliably if given a dry dormancy.  For convenience, I store my bulb completely dry in the cool, dark crawl space of our house during the winter.  When I bring it out in the spring, it starts growing very rapidly and usually flowers within two weeks of the first watering.  The flowers are very fragrant, though rather short-lived.  Often, a second or third inflorescence will follow in a few weeks.

The leaves, forming a loose rosette, continue lengthening as long as water is available but turn yellow and detach at the level of the bulb when the soil dries out.  In the photo above, the leaves have blunt, squared-off tips, because they died back to the bulb last autumn.  Any new leaves that emerge from the center of the bulb will have more tapered tips.

I suspect A. coranica would be hardy in the piedmont if the bulb were planted deep enough, but the rather short inflorescence is probably better displayed in a pot.  My plant has not produced any offsets, and it does not seem to be self-fertile.  I should have bought more than one bulb when I had the chance.

(Note to self:  when photographing plants late in the day, remove white I.D. tags that reflect the setting sun.)

First bloom: Eucrosia aurantiaca

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Inflorescence of Eucrosia aurantiaca

Currently blooming for the first time in my greenhouse is an unusual South American bulb that I purchased in 2015.  Eucrosia aurantiaca is an amaryllid from south central Ecuador, where it grows in semi-desert hills and canyons dominated by Acacia scrub [1].  With its extemely elongated stamens and style, it resembles the related species Eucrosia mirabilis (see previous blog post), but the slightly flared yellow tepals of E. aurantiaca are altogether more attractive.  E. mirabilis looks more like a mop or strange jellyfish.

Eucrosia_aurantiaca4

I grow my E. aurantiaca rather like a succulent or cactus.  It is planted in a terra cotta pot with a fast draining mix of sand, permatill, and a little potting mix.  It spends the summer outside in full sun and has a long, dry dormancy in the greenhouse during the winter.  Because the greenhouse is heated for lowland tropical plants, the temperature never dips below 60 F (~15 C), and I don’t know how E. aurantiaca would react to cooler temperatures when dormant.  Under these conditions, I find Eucrosia species easy to grow and bloom, certainly more so than many Hippeastrum which do not seem to appreciate the hot summer and warm winter.

My E. aurantiaca bulb has not offset, so hopefully it will prove to be self-fertile like E. mirabilis.

Reference

Meerow, A. W. (1987).  A monograph of Eucrosia (Amaryllidaceae). Systematic Botany 12: 460-492.