The Brazilian Beauty, Laelia purpurata

Laelia purpurata carnea

June is a terrific month to see some of the showiest orchids in our collection. The Laelia purpurata* varieties, Stanhopea species and Anguloa (Tulip Orchid) species make a wonderful early summer combo. However, it is the Laelia purpurata varieties who are the undisputed stars of early summer. They pretty much own the Orchid Center for from late May until July.

Laelia purpurata 'Adam's' x "alba"

Laelia purpurata is enormously popular with orchid growers in warm countries, especially in Brazil, in the states of Rio Grande do Sul, Santa Catarina and Sao Paulo, where it grows in coastal areas. Laelia purpurata is the state flower of Santa Catarina.

Laelia purpurata werkhauseri

Among Brazil's many annual floral shows the Joinville Flowers Festival in the state of Santa Catarina is the largest featuring Laelia purpurata. The festival, which hosts varied floral exhibits, scientific lectures, orchid judging, music and dancing, is dominated by the presence of Laelia purpurata and its many varieties. In recent years the festival's visitation has reached nearly 200,000.

In Atlanta Laelia purpurata is easy to grow in a warm (65º night minimum) bright greenhouse.They love Atlanta's long warm summers.We grow our plants in clay pots in a standard Cattleya mix of medium grade fir bark, charcoal and sponge rock. They grow quickly and make handsome specimen plants. Stop by and see them!

*some recent synonyms:
Cattleya purpurata Van den Berg (2008)
Sophronitis purpurata Van den Berg & Chase (2000)

Encyclia prismatocarpa

Encyclia prismatocarpa

Here is one of my favorite encyclias. Encyclia prismatocarpa grows as an epiphyte from Mexico through Central America at 1200 to 2500 meters. I love the leopard spots on the petals and sepals.

Until recently our plants grew well in our intermediate greenhouse, but with the trend toward warmer summers, they seem to prefer the Tropical High Elevation House, where the daytime temperatures stay below 77º. We were pleased to acquire the plant pictured above, an especially vivid color form, from Andy's Orchids this spring. It is flowering this week in a pot in the Orchid Display House. After flowering we will install it in the High Elevation House. A terrific orchid!

Dendrobium aphyllum

Dendrobium aphyllum in late April and early May in the Orchid Display House. 

Dendrobium aphyllum is amazing. The medium-sized plant pictured above produced more than one hundred flowers this spring. Almost every node on the gracefully arching pseudobulbs produced a pair of lavender flowers, each with a densely fuzzy white lip. For me, it's the plush velvet lip, not simply the floral production, that makes this orchid irresistible. 

Dendrobium aphyllum grows in India, Myanmar, Thailand and south China at 200 to 1800 m in seasonally dry tropical forests. The plant produces new leafy shoots in the spring that eventually become long slender pseudobulbs. The pseudobulbs shed their leaves after about a year. (Aphyllum means leafless.) Buds form in winter on the mature pseudobulbs.

In cultivation D. aphyllum (and similar species like D. anosmum) will thrive on a slab of tree fern, cedar or cork, or in a hanging basket to accommodate the pendant pseudobulbs. Our plant is mounted on a slatted cedar slab. A small slatted basket creates a healthy environment for roots, but can become quirkily lopsided if the plant insists on directing all of its new growth to one side.

Our plant gets the spa treatment in summer in a warm moist greenhouse. In November we move it to a cooler (53º nights) brighter greenhouse and back off the watering somewhat until January when the buds are visible. Aside from a thorough watering every ten days or so, it needs no maintenance at all during its winter rest. A terrific plant!

Nothing Says Spring Like Dendrobium

 Dendrobium lindleyi

For two incandescent months from mid March to mid May the Callista Dendrobium species illuminate the Fuqua Orchid Center. It's as though they want to join the burst of spring bulbs during Atlanta Blooms.

These beautiful and tremendously rewarding dendrobiums deserve greater attention from commercial growers and hobbyists.

Dendrobium lindleyi

What is a Callista Dendrobium?
The genus Dendrobium is so large that it has been divided into sections, based on general similarity. Dendrobium section Callista* contains 10-14 of the most admired species in the genus.

Dendrobium thyrsiflorum 

Callista dendrobiums grow in mainland southeast Asia at intermediate to high elevations in areas with a pronounced dry season. During the winter dry season Callista Dendrobium species that grow in deciduous forests experience cooler temperatures and brighter light.

Dendrobium thyrsiflorum, an early spring Narcissus wannabe

In cultivation Callista Dendrobium species need a moist tropical summer followed by a dry rest (often a cooler dry rest) in winter in order to initiate buds. Our plants receive 53º night temperatures and are watered less frequently from Thanksgiving through New Year's. This change in temperature and watering routine requires very little effort on our part.

Dendrobium chrysotoxum 

It seems insane to be so lavishly rewarded for so little effort! It's certainly not hard to figure out a way to water less frequently. If you manage the temperature drop you should definitely consider growing the Callista dendrobiums.

*Syn. Densiflora

Openings: Week of May 7

A whiskered Rhyncholaelia digbyana caught in mid-yawn, no doubt awaiting its nocturnal pollinator. Like many other orchids with a nocturnal moth pollinator,  Rhyncholaelia digbyana is night fragrant. The green tongue at the center of the flower is called a callus.

 Schomburgkia lyonsii, a lovely Caribbean species, holds a bouquet-like raceme of flowers atop a three foot tall spike.

Laelia purpurata var. werkhauseri, one of the most sought-after of the purpuratas, is flowering a month early in the Orchid Display House.

Oncidium spahacelatum ignites the circular bed of Mexican orchid species.

Epidendrum embreei flowers almost continuously at the base of the waterfall in the Tropical High Elevation House.

Stop by the Fuqua Orchid Center during Cocktails in the Garden this Thursday evening!

Is There a Blue Orchid?

Dendrobium victoriae-reginae flowering this week in the Fuqua Orchid Center

There are a couple contenders for the 'Blue Orchid' crown. One of them is the royal blue Dendrobium victorieae-reginae.

This beautiful orchid with pendant pseudobulbs and waxy blue-violet flowers is native to the Philippines where it grows at moderately high elevations (1300 to 2600 m) in wet mossy forests.

Our plants are permanent residents of the Tropical High Elevation House where they grow at eye level on a driftwood tree. The forests in which this species grows never experiences a regular dry season, so our cultivated plants are watered throughout the year.

The name victoriae-reginae denotes that the plant was named in honor of Queen Victoria whose Golden Jubilee was celebrated around the time of its discovery in 1897.

The other species that that comes up in any discussion of blue orchids is Vanda coerulea (coerulea= sky blue) which has imparted its blue violet pigment to many richly colored hybrids.

Both of these orchids are extremely popular. What do you think--does either orchid deserve the name 'Blue Orchid'?

Why An Early Spring Means Trouble

Laelia purpurata 'Adam's' x "alba"  flowering this week in the FOC*

We had an exceptionally mild winter this year followed by a very early spring. Atlanta's dogwoods flowered a month before the Dogwood Festival.

Greenhouse plants are not exempt from the effects of an early spring. I was only slightly surprised and a little dismayed this week to see the first flush of flowers on our bench of Laelia purpurata orchids. They typically flower for us in late May and June.

Why dismayed? In a normal year Atlanta's plants have to endure almost four months of daily daytime temperatures above 90º. Ninety degrees outside translates into 85º in the greenhouse when the humidity is high.  Laelia purpurata certainly doesn't mind the heat, but our soft-leaved intermediate growing orchids begin to show signs of heat stress after four months. Since the daytime temperatures are already above 90º, they have a long slog ahead. A few years of this and some of these orchids will simply disappear from our collection.

Just as worrying is the effect of the mild winter and prolonged summer on pest populations. Aphids and some thrip species originate outdoors, so a population boom outdoors spells trouble indoors or in a greenhouse where there are no natural predators.

Resident populations of scale and mealybugs can also explode. As temperatures rise the generation time (the length of time an insect needs to become reproductive) shortens. A long hot summer means many more generations of pests at work on a population of plants already weakened by heat stress.

Stanhopea tigrina flowering on May 1

Moreover, hot conditions limit our use of our favorite low toxicity pesticide, Neem oil, which can harm a plant that is heat and drought stressed. I would hate to have to resort to conventional pesticides because of the heat. This year we started our spray cycle with Neem oil a month early.

One weapon that I have at my disposal is the ability to manipulate the greenhouse environment. By programming the exhaust fans and evaporative cooler to run not just during the day, but also during the coolest part of the night (3 am to 6 am) I can drive down the night temperature to a reasonable level.

Even so, we're in for a long battle.

*Synonyms:
Sophronitis purpurata Van den Berg & Chase (2000)
Cattleya purpurata Van den Berg (2008)

Embreea rodigasiana

Embreea rodigasiana flowering this week in the Fuqua Orchid Center

In the back up greenhouses at the Atlanta Botanical Garden is a bumper crop of seedling Embreea orchids that have just reached flowering size. They are making their debut this month in the Orchid Display House. Embreeas are considered to be rare and difficult in cultivation, so we are delighted to be able to show them to you.

Embreea is a striking orchid that resembles the closely related genus Stanhopea. It shares with Stanhopea the pollination syndrome associated with male Euglossine bees,--large tropical bees that collect fragrance. The waxy flowers are huge (about four inches) and their eucalyptus-like fragrance is highly attractive to Euglossines. The flower points downward and the column and lip together form a chute to guide the bee past the pollen masses located at the tip of the column.

Embreea produces a single-flowered spike, rather than the massive multiple flowered spike of Stanhopea. The horns on the lip have a very distinctive hatchet shape.

Since Embreea rodigasiana comes from an especially wet area of western Colombia--the Choco region--we water our plants more frequently than we do our stanhopeas. Embreeas absolutely need a humid greenhouse in order to flourish outside of the warm tropics. Our plants do well in a mixture of New Zealand sphagnum and chopped tree fern fiber. A wire or net basket is needed in order to accommodate the pendant spike which often grows downward through the medium.

Don't miss these! You can find them in the Orchid Display House this month in baskets hanging below the beams of the cedar pergola.

Horizontal Twist II

Horizontal Twist, 2008, Beverly Pepper (American b. 1922)

I hate rust. All greenhouse managers hate rust. Rust is the enemy, the relentless destroyer of greenhouses.

Why, then, is the surface texture of Horizontal Twist so appealing? The richly colored scurfy surface of COR-TEN steel, is, after all, rust. (Okay, okay, call it an oxidated surface.)

It was Sarah Carter of our staff who drew my attention to the magnificent staghorn ferns directly above the sculpture.

Platycerium wandae

The thick carpet of rusty spore patches on the underside of the fronds matches the sculpture perfectly in color and texture.

A closer look at the beautiful rust colored spore patches 

Staghorn ferns, like our Platycerium wandae, produce two different types of leaves: clasping shield fronds that surround the root ball and attach the young sporling to a vertical surface; and the staghorn-like fertile fronds which develop spore patches when mature. Our staghorns produce a tremendous quantity of rust colored spores that germinate readily on the cedar pergola.

Schefflera macrophylla stem

Ferrugineous (ferrum = iron) is the Latin adjective for rust colored. Staghorn ferns aren't the only example of ferrugineous surfaces in nature. Schefflera macrophylla from south China & Vietnam wears a velvet mantle of rusty hairs on its stem and petioles.

Rhododendron konori

Rhododendron konori, one of the Vireya Rhododendrons in the Tropical High Elevation House, produces leaves and buds covered with an attractive dusting of rusty scales (which are multicellular epidermal hairs).

Horizontal Twist, with its lovely patina of rust, looks entirely at home among these plants. Who would have imagined that rust could be so beautiful?