Two bulb experts, Michael Hagen, Curator of the Rock Garden and Native Plant Garden, and Marta McDowell, NYBG instructor, author, gardener, and landscape historian, recently commented on some frequently asked questions about the gorgeous spring bulbs now blossoming in the garden . Here’s what they had to say.
Q: What are some of the easiest spring/early summer bulbs to grow?
McDowell: Narcissus seem to be almost indestructible and with so many varieties, you can have them in bloom for almost two months. Other choices: Crocosmia—graceful in leaf and flower and blackberry lily (Iris domestica or Belamcanda chinensis). Great foliage, flowers, and seed pods.
Q: What are some of the most difficult bulbs to grow, aside from climate issues?
Hagen: Climate aside, the hardest to grow are the ones that our native ground squirrels, chipmunks, woodchucks, and gophers enjoy eating. Species tulips have been a particular challenge in the Rock Garden. If it’s a warm fall (and the chipmunks are not hibernating yet) they can be dug up and eaten right after they’ve been planted.
When I talk to other botanical enthusiasts about wildflowers of the northeastern United States, our conversations often return to the same question: “Where have all the spring wildflowers gone?” The most obvious response is that there are too many deer eating understory plants in our forests. However, that is only one of several reasons explaining the loss of spring wildflowers, among which is the presence of invasive plants which outcompete many species of our native flora. One of the worst invasives, the Japanese barberry—Berberis thunbergii DC—has had a major impact, leading me to rate it as one of the most noxious invasive plants in the northeast.
After seeing what I have to say, I would love to know if you can nominate an invasive species nearly as bad as this resource glutton!
Of the many spring ephemerals cropping up in the Garden, the plant known as “spring beauty” in the genus Claytonia is one that can be seen without taking a walk through the woods. It is commonly found at the edge of woodlands, or along mowed roadsides. Like many spring ephemerals spring beauty flowers close at night and remain closed on overcast days. This tendency, combined with the plant’s grass-like leaves, make it easy to miss spring beauty if you do not look closely.
The beauty of spring beauty is best enjoyed by looking closely at the flowers with a hand lens. This allows you to appreciate the delicate pink lines that lead insect visitors to the source of nectar at the base of each petal. Insects–among them small bees, flies, and wasps–are further guided to the nectaries by a bright yellow spot; they are attracted by both nectar and pollen. The tiny flowers do not produce enough nectar to warrant a visit by the large queen bumblebees that fly in early spring, but small bees drink their fill and pack their pollen baskets with the anthers‘ creamy white pollen. The anthers themselves are pink and open before the female reproductive parts, thus helping to promote cross-pollination.
It is beautiful here today. Just in case you can’t make it out of your office to hop a train and come up to the Bronx, I thought I’d take a walk and snap some pictures for you. It’s more than just beautiful out, too. According to one birder I met today, it’s also prime warbler migrating time. As he put it, the next two weeks will be “warbler heaven.” So whether you’re a birder, photographer, gardener, or walker, now is the time to come and visit the Garden!
In the early spring wildflower parade, Dutchman’s breeches (Dicentra cucullaria) follow closely on the heels of hepatica, blooming by mid-April. Dutchman’s breeches are one of the true spring ephemerals, plants that complete their entire above-ground life cycle within a period of only a few weeks and then disappear until the following spring. Of course, the underground portions live on, storing the carbohydrates manufactured by the leaves during the brief period before the trees have leafed out and shaded the forest floor. But spring ephemerals are not roadside plants.
To see most of our native ephemerals requires a pleasant walk in the woods. Ephemerals are plants that have evolved to live in the primeval conditions of Eastern North America—a land once covered by forest. They must take advantage of the short period of year when temperatures are warm enough and sunlight sufficient enough on the forest floor for the plant to accomplish three tasks: food production, reproduction, and storage of carbohydrates for the subsequent year’s growth.
When walking in the woodland area of the Native Plant Garden this time of year, you will meet up with the native fern Polystichum acrostichoides, commonly known as the Christmas fern. These ferns can form large, one- to two-foot clumps; are easy to grow; and are standouts in winter due to their evergreen leaves.
The individual leaves on each frond are stocking-shaped, reminiscent of Christmas stockings, which some people claim is the origin of the plant’s common name. But, in fact, the name “Christmas” fern comes from its having deep green fronds at Christmas time, says NYBG fern expert Robbin C. Moran.
Dr. Moran’s entertaining and enlightening book, A Natural History of Ferns, (available in the NYBG shop or by print-on-demand from Timber Press), explains how these amazing plants reproduce by actually “shooting” their very tiny spores. “The spores leap more than an inch into the air and arch downward,” Moran observes. “It is like watching popcorn popping.”
The spring trout lily (Erythronium americanum) is one of several native perennial wildflowers blooming now in the Native Plant Garden. Its flowers appear in sunny patches in the forest woodland area. At the base of each plant are its telltale leaves—speckled, elongated, and looking like brown brook trout.
The flowers come up quickly in the early spring, then produce fruit and create new leaves, all before the tall, deciduous trees leaf out and block much of the sunlight. In the heat of summer, the flowers and foliage disappear, which is why they are called ephemerals.
Some other examples of native ephemerals are blood root (Sanguinaria canadensis), liver’s leaf or hepatica (Hepatica nobilis), and Dutchman’s breeches (Dicentra cucullaria). But the trout lily is by far my favorite for there are so many stories about it.
The leaves of Virginia bluebell sprout each spring in such deep shades of purple that they are difficult to see against the dark soil. As the leaves mature, the purple coloration is gradually lost until they become a soft green. Flowers, too, undergo a color change, from pink in bud to a lovely shade of blue shortly before the buds open.
The floral color change is not uncommon in members of this family, the Boraginaceae (borage family). Its members include forget-me-not (Myosotis spp.), viper’s bugloss (Echium vulgare), and lungwort (Pulmonaria spp.), all of which have pink buds opening as blue flowers. The color change is due to changes in the pH of the cell sap, and, like some hydrangeas, plants growing in more acidic soils will have flowers of a deeper shade of blue. Members of the borage family also share in common the shape of their inflorescence, referred to as a scorpioid cyme for the way it uncoils like a scorpion’s tail. A true spring ephemeral, the leaves of Virginia bluebells turn yellow soon after the flowers have finished blooming and are gone by late June.