One of many beautiful poinsettias at the US Botanic Garden

I’ve been to the US Botanic Garden (USBG) many times and have always enjoyed the beautiful displays that change with the seasons. But in December, I bypass the holiday dazzle of the evergreen-draped lobby, work my way through the steamy medicinal plant and orchid gardens and head straight to the restrooms. There, behind the glass atrium in a quiet passage all its own is the USBG’s best-kept secret: a one-of-a-kind poinsettia display.

And the collection grows year after year to include an increasing array of spectacular varieties. Sharing the limelight with the traditional reds are the latest, eye-catching hybrids in bright white, soft yellow, light pink and salmon. There are marbled varieties, spotted ones and some that are the result of crossbreeding with other species (more on that below.)

US Botanic Garden poinsettia passage

The effect is of a rich winter garden filled with unusual, multi-colored flowers. Luckily there are benches just across where a visitor can sit back and take it all in.

THE LEAF IS NOT THE FLOWER

It’s important to note, when looking at a poinsettia, that it’s the bracts (modified leaves) that provide the color. The real blooms are the tiny yellow buds called cyathia in the center. Once the flowers have shed their pollen, the plant drops its bracts and leaves. Because of this, it’s always good when shopping for a poinsettia to select a plant with little or no pollen showing.

Poinsettia flowers are yellow

Poinsettias are referred to as a short-day photoperiod crop, meaning they naturally flower once the nights become longer. To create their colored bracts, the plants require at least 12 hours at a time of darkness over a period of at least five days in a row. Once they have completed the process, however, poinsettias require bright sunlight during the day to attain the brightest color.

ONCE CONSIDERED A WEED

In its native Mexico, the poinsettia is a perennial flowering shrub or small tree that typically grows to a height of 10 to 15 feet. A member of the spurge family, it goes by the botanical name Euphorbia pulcherrima. Poinsettia shrubs were once considered weeds. Today they are the best selling potted plant in the United States and Canada, with more than 100 varieties available.

A poinsettia shrub as it might appear in the wild

The Dogwood poinsettia, Euphorbia cornastra, was first discovered in 1973 growing in the high elevation tropical forests of Mexico. Although similar in growth habit and inflorescence to Euphorbia pulcherrima, it has gray-green foliage and is summer flowering. Dogwood poinsettia is prized for its pure-white bracts. This year’s display includes a stunning example.

Dogwood poinsettia, Euphorbia conastra

Close-up of Euphorbia conastra’s brilliant white inflorescence

WHITE VARIETIES FOLLOWED THE TRADITIONAL RED

The first white poinsettia varieties were introduced in the 1970s. Since then, there have been many improvements. An example is Euphorbia ‘Princettia Pure White’, which features pure white bracts and barely visible flowers. The Princettia series has a unique bract form whose blooms mature early, resulting in a more clean-looking ‘flower.’

CROSS-BREEDING SPAWNED AN ARRAY OF NEW COLORS

Growers have been tinkering with hybrid poinsettias for some time now, making the plants more compact and increasing their longevity. The past five years, though, have seen a surge in cross-breeding specifically to produce unconventional colors. The new hues are created by crosses between poinsettia and other euphorbia species.

‘Luv U Pink’ is one such variety produced by the Paul Ecke Ranch for Breast Cancer Awareness. Its hot pink bracts have a thin, pale pink edge. The bracts have an otherworldly iridescent shimmer.

Euphorbia ‘Luv U Pink’

A newer variety incorporates a white splash.

Euphorbia ‘Luv U Pink Splash’

YOU CAN’T LOSE THESE MARBLES

The marbled varieties, first pioneered in the 1970s, provide a spectacular contrast to the traditional reds. I love their painterly quality, almost as if someone has splashed them with a brush.

Euphorbia ‘Red Glitter’

Euphorbia ‘Peppermint Ruffles’

Euphorbia ‘Christmas Feelings Red Cinnamon’

Euphorbia ‘Ice Punch

PRETTY IN PINK

Then there are the soft pink varieties, which provide a quiet respite from all the bright hues. Among them, these three are US Botanic Garden standouts:

Euphorbia ‘Luv U Soft Pink’

Euphorbia ‘Princettia Pink’

Euphorbia ‘Autumn Leaves’

BACK TO BASICS

Of course, traditional red still makes up the bulk of the sales, with growers hesitant to spend the time and money it takes to develop too many new varieties. Usually they choose just a couple to focus on and leave the rest of their energy for the reds. Below, USBG’s 2017 display includes Euphorbia ‘Jester Red’, Euphorbia ‘St. Louis’ (shrub) and a beautiful rose-shaped variety called Euphorbia ‘Winter Rose Early Red’.

Traditional reds: Euphorbias ‘Jester Red, ‘St. Louis’ and ‘Winter Rose Early Red’

Close-up of Euphorbia ‘Winter Rose Early Red’

Before you go rushing to the nursery (as I did) to purchase some of these gorgeous new varieties, though, it’s worth noting that many are not yet commercially available. Still, I was delighted to find two varieties of the marbled ‘Jingle Bells’ at my local grower. Here’s hoping more hybrids come onto the market in the coming years.