Friday, November 30, 2007

Notes from Around Town: NYBG and Winter Interest

The other day I was invited up to the New York Botanical Garden for a meeting and luncheon. I joined a number of other green organizations, land trusts, city and state departments, and representatives from the Brooklyn Botanic Garden and New York Botanical Garden to discuss the importance of community gardens, our role in their success, and what needs to be done in the future to ensure their longevity. As a 105-year-old nonprofit here in Manhattan, HSNY is an organization that provides all the same offerings as the larger botanical gardens: educational resources including classes and a library, research and statistics based on our exemplary outreach programs, horticultural phone and email support, consultation services, numerous events throughout the calendar year, horticultural services, and experienced horticultural staff who train and educate communities throughout New York City. This year we are celebrating the 10-year anniversary of both the Riker’s Island Greenhouse program and the community-based GreenBranches program, two of our exemplary outreach programs that prove that horticulture improves the quality of life for a wide range of local communities. Our GreenTeam, graduates of the Riker’s Greenhouse, have worked closely with other social service organizations and the land trusts providing horticultural services, workshops, and horticultural therapy in community gardens throughout all of the boroughs. We enjoy sharing with other green groups our experiences to help aide with the communal goal of successful, sustainable greening of our city. And it was a fabulous meeting of the minds. I can say without hesitation that I am thrilled to be a horticulturist living and working in the city during these times of necessary and beneficial change.

But, of course, I couldn't leave without getting out and taking some pictures of the trees and shrubs I love so much this time of year. Everyone else was headed to the conservatory to get a tour of the Holiday Train Show, but I snuck away and reunited with some of my old friends. This time of year some people have the nerve to say nothing is happening in the garden, and I must say that absolutely boggles my mind. It is true that many leaves have fallen and many herbaceous plants have died back already, but there is still so much interesting fruit-set and seed, bark, and forms in the landscape.
Malus ‘Red Jade’ is a weeping form of a flowering crabapple, a member of the rose family, Rosaceae. The white flowers that bloomed in spring have led to the glossy red fruit that hang off the dark, pendulous branches. This specimen is mature, spanning 15’ wide and almost as tall. I love the combination of the dark, textural bark and the red fruit, which the birds love as well. Even here in some shade the fruit-set suggests that the tree put out a decent amount of flowers.
Newer cultivars of flowering crabapples are now being bred for even greater fruit set in the fall,not to mention variations in color. Here is a young Malus ‘Sugar Tyme’ and below it, with the yellow-orange fruit, is Malus transitoria ‘Golden Raindrops’. Then there is Callicarpa japonica, or Japanese beauty berry. A deciduous shrub, beauty berry loses its simple, toothed leaves in fall, leaving at the nodes these clusters of purple fruit. The shrub, which typically reaches about 6’ tall and wide, has an upright arching habit that might not be interesting enough for some. However, the 2” clusters of unique purple berries that cover the shrub this time of year certainly make up for its rather ordinary form. Planted amidst a woody border, the contrast of colors this time of year would be sensational.
Rhus typhina is called staghorn sumac. A North American native, found from Georgia up to Quebec, staghorn sumac is a very durable shrub with its open habit and large compound leaves. This cultivar, ‘Laniciata’, has very deeply divided leaflets that almost look fern-like and have great fall color. Here all that is left is the hairy crimson fruit atop the bare branches which will remain through winter.
While we are on the topic of North American natives, here are two shots (above and below) of an Ilex opaca, or American holly. With their large, pyramidal habit that reaches taller and wider than most hollies in the northeast landscape, it is a beautiful staple for fall.

Ilex verticillata, commonly called winterberry, is yet another native Ilex for our region. As you can see this member of the holly genus is deciduous, but who needs leaves when you have the stems so covered with bright red fruit through the fall and winter. I have had the most success with this plant when placing it in full sun in an area that stays moist on a regular basis. Certainly for the best fruit-set you are going to want to provide these upright shrubs with as much sun as possible. Some references say that winterberry can tolerate dryer soils as well, but I'm still testing those hypotheses.
I have talked about redosier dogwood in the past, botanically known as Cornus sericea, and here it is in front of a stand of tall grasses. The bare red stems in fall have great character on their own, especially when combined with more natural colors and hues like these tall grasses behind them.

While we are on the topic of combinations, here are a few that caught my eye and I wanted to share them with you.
In the background is bluestar (Amsonia hubrechtii) and in front a small globe blue spruce (Picea pungens 'Glauca Globosa'). The Amsonia is past its prime, but imagine a soft, glowing yellow in contrast to the striking blue of the spruce. All over the garden the blue spruce were stunning.
Or how about the dried blossoms of a Hydrangea with a more typical green conifer far behind? All through the summer people can forget that green foliage is a color in itself, but the fall and winter is a great time for evergreens to shine.
Here a kind of pine is wedged between a large Euonymus shrub in the foreground and a huge Taxodium in the background. The rest of the year it is hidden but this time it looked so full and rich and vibrant.

Of course, in the fall you do not want to forget about viburnums. Most of us know viburnums because of their spring flowers and fragrance, but plenty of species remain interesting well into the fall. This is Viburnum setigerum, commonly called a tea viburnum. The russet fall color and clusters of hanging red fruit makes this one of the most popular viburnums for this time of year. This upright, multi-stem shrub is a slow grower, but give it time and you will end up with a specimen that stands a good 6'-8' tall and nearly as wide.
Lastly, I had to take a picture of the Choctaw crapemyrtle (Lagerstroemia x indica 'Choctaw'). Those of you who know me well know how I am infatuated with these trees, and yet again I say, "well, why not!?" I've talked about the upright habit of these small-to-medium trees and their exfoliating bark. I've mentioned the late summer flower than can range from soft pink to brilliant magenta. And here I am, underneath the almost black clusters of dry fruit that sit at the outermost tips of the branches. Combined with the cinnamon bark and against the amazing blue of the fall sky, now that's a form in nature I'll appreciate all winter long.

Thursday, November 29, 2007

Plant ID: Lysimachia clethroides (A Discussion on Potential Invasives)

Gooseneck loosestrife (Lysimachia clethroides) is a member of the primula family, Primulaceae. It is native to China and Japan, and therefore is an introduced species here in the United States. It has upright stems with long, narrow foliage that are 3” or 4” in length. The plant grows about 2’ to 3’ tall and spreads by fast-growing rhizomes as well as by seed. In late summer the plant produces spires of white blossoms right above the foliage that grow in beautiful curvy and contorted forms, hence the name. Gooseneck loosestrife grows in full sun to part shade and is adaptable to a wide range of soil conditions. It is hardy in USDA zones 4-9. But beware, just because it sounds and looks like a beautiful plant does not mean you shouldn’t still do your homework.

I was first introduced to this plant when I found it growing outside of my father’s retail shop in the Hamptons years ago. Next to a formal herb garden that I planted outside the storefront window was an unkempt space and in it was growing gooseneck loosestrife. My father enjoyed the plant, its persistence, and late summer flower, so we left it in the area and let it do its thing. In fact, when my father closed the shop he liked the plant so much that he divided a piece from the mother plant and transplanted it to my parents garden at home.

If only I knew then what I know now.

After a few years my father called and explained that the loosestrife was quickly taking over my parent’s garden and asked how he might control it. We talked about the multitude of small black seed that follow the profuse spires of white flowers and I recommended deadheading the flowers before they passed maturity to prevent the seed from forming. I also taught him about the aggressive underground rhizomes and explained that he would have to remove them entirely to ensure that the plant did not come back. Lastly he asked if he could move it to the other side of the driveway, which happened to be adjacent to a portion of natural woods. I exclaimed, “No, you can't do that!” Plants that become invasive in home gardens are bad enough, but when they spread to natural woodlands then the problem can become exponentially worse practically over night. Had the gooseneck loosestrife been allowed to drop seed and spread it’s rhizomes into the woods then there would be nothing holding it back. As an introduced species with no natural predators, whether they be other plants, feeding insects, or diseases, the plant would eventually begin to overtake our important native plants, ferns, and mosses. It sounds hard to believe that one transplant could disrupt an entire ecosystem, but unfortunately I have seen it happen entirely too many times.

Burning bush (Euonymus alatus) is perhaps one of the best examples. Originally chosen and planted in American gardens because of its brilliant red fall color, burning bush is an introduced species with no natural predators. Planted in suburban lots all over the northeast the seeds eventually spread into nearby woods and began to produce multiple seedlings. Now, from southern New Jersey to northern Massachusetts natural forests and woodlands are being disrupted and native species are losing the fight against this invasive shrub. Driving in the fall you might not think anything is wrong as you see patches of the bright red shrub amidst your local woods, but a trained horticulturist will be quick to tell you otherwise. Organizations devoted to restoring natural ecosystems and habitats can no longer attempt to eradicate the problem and the plant populations that have run rampant; the best we can do now is to control the infestations as best we can. Some states have made great strides to make invasive plants illegal to buy or sell, but I am sorry to say you can still find burning bush for sale in New York State.

You can tell this is a topic I feel strongly about. Therefore you can imagine how my emotions flared when a woman called recently to ask about how she could get rid of a patch of gooseneck loosestrife in her garden in New Jersey. I explained the profuse seed production and the aggressive rhizomes and she knew the characteristics all too well. Year after year she dug up as much as she could, even resorted to Round-Up, an extremely strong chemical herbicide that should only be used as a last resort, and still she would find new growth every spring. I believe she said it is now the fifth year of her battle. I tried to find feeding insects that she might introduce to her garden that would target the gooseneck loosestrife, but to no avail. There are more heavy duty herbicides on the market, but in a condensed residential neighborhood I could not ethically recommend introducing them for fear that if wrongly applied they might leach into the ground water. After much research and many conversations it was frustrating that the best piece of advice I could give her was to not lose hope, to keep up the fight, and to reaffirm that she was doing everything right.

So, what lessons can we learn from these overwhelming tales? While conservation and native plant advocates fight for stricter policies regarding the growing and sale of invasives, (insert applause here), it is our duty to be the best educated consumers we can be. Gooseneck loosestrife, to the best of my knowledge, is still not considered invasive. I even found a few websites that listed it as an “ideal garden plant”. Obviously I beg to differ. The next time you see a plant at the nursery that you are new to, consider doing a little research before taking one home and planting it in your garden. If it is an introduced species from another country, even if it has been introduced for centuries, see if you can find out if it has any tendencies towards becoming invasive. In this regard a little internet or book research can be invaluable for the long run. Better yet, see if there is a native alternative that might work just as well in your landscape plan.

Monday, November 26, 2007

HSNY Movie Screening: Rivers and Tides

(photograph of Andy Goldsworthy from the film Rivers and Tides)

Come join us for a viewing of Rivers and Tides on Tuesday evening, November 27th, from 6:30 - 8:00pm at the HSNY Headquarters (details below). Directed by Thomas Riedelsheimer, Rivers and Tides is the 2001 documentary of Andy Goldsworthy, acclaimed installation artist and photographer. The film includes commentary by the artist as well as breathtaking footage of the process and product of his artistic endeavors, both in the States and abroad. You have likely seen Goldsworthy's coffee table books and impressive photography, but wait until you see how his work really comes to life in this insightful and inspiring documentary.

Movie Screening: Andy Goldsworthy’s Rivers and Tides
Tuesday, November 27, 2007, 6:30 – 8:00pm
Free for members, $5 suggested donation for nonmembers
The Horticultural Society of New York
148 West 37th Street
13th Floor
New York, NY 10018

Monday, November 19, 2007

Plant ID: Paphiopedilum sp.

This is a kind of Paphiopedilum, an orchid commonly known as a slipper orchid. As members of the largest flowering plant family on earth, Orchidaceae, there are slipper orchids indigenous to both the Old World and the New World. New World slipper orchids, those native solely to the Americas, are known by the genus Phragmipedium. Cypripediums are slipper orchids that have been found in the Americas as well as Europe and Asia. Paphiopedilums are considered Old World slipper orchids and are native from India across southern China to the Philippines and New Guinea. Within the genus Paphiopedilum there are terrestrial species, which grow in leaf litter on the forest floor, lithophytic species, which grow anchored on limestone cliffs, and epiphytic species, which grow on other plants. The one above that I bought and added to my collection is an epiphytic species. You can tell this by the free-draining yet moisture retentive mix of fir bark that the plant is grown in, meant to resemble the environment in which they would naturally grow, in the crook of a tree perched high up in the rainforest. Many orchids have pseudobulbs which are large bulbous growths that retain and store excess water and nutrients for times of drought. Paphiopedilums, however, do not form pseudobulbs and instead do all of their water and nutrient storage in their thick, fleshy leaves. You can see that the slipper orchid I bought has an attractive mottling to its leaves. Paphiopedilums have been found at every elevation from sea level to 7,000 feet above sea level and higher, and those found in lower, warmer situations tend to have this characteristic leaf pattern. Now, certain orchid growers will tell you that both the solid-green and mottle-leafed Paphs can be grown with equal success, but since this is my first of this genus, and our city apartments can get so overheated, I thought I'd stick with one that I felt might adapt better to the environment I can provide. That and the mottled leaves will continue to provide some visual interest even after the flower has passed. This beautiful slipper orchid will prefer night temperatures a good 10 or 15 degrees cooler than the day, so I have placed it near a window where I hope it might get a chance to cool off a little bit at night. We cannot always provide the ideal conditions for plants we choose to grow as houseplants so we simply have to do the best we can. Otherwise I will provide it with general orchid care: water once a week in winter and perhaps more often in the summer when the plant is more active; keep a tray of moist pebbles underneath the pot to provide some additional humidity in the immediate area around the orchid; and continue to grow it in an area of bright, indirect light with no direct sunlight for any length of time. I bought this plant a month ago and the initial flower is still holding up very well. Remember, if you want your orchid flowers to hold up, you must provide the plant with some extra added humidity. There is a second bloom on the flower spike, another reason I chose this specific specimen, and after a month that is just beginning to open. Lastly, there was one final reason I chose to buy a Paphiopedilum and I will share that with you as well. Orchids have a growth habit that is either monopodial, or sympodial. An example of a monopodial orchid is a Phalaenopsis, or a moth orchid, that typical white orchid you see everywhere. Upon examining the plant you will see that all of its new growth emerges out of one single growing point at the top of the plant. Orchids with sympodial growth habits, on the other hand, put out new growth from the base or the sides of preexisting foliage. Look again at the foliage picture above. See the main growth where the flower stalk is rising up, and then see the new leaves growing up and out to the left of that? Well, that new growth will eventually grow into a plant of its own with its own flower spike. If it gets large enough I hope that some day I may be able to sever it from the mother plant and continue to grow on its own. In general I like to buy and grow orchids with sympodial growth habits (Paphiopedilum, Oncidium, Cattleya, etc.) because even when the plant is not in flower there is typically enough new growth of foliage that the plant is still large and interesting enough as a houseplant.

Thursday, November 15, 2007

Notes from Around Town: Ford Foundation Atrium

As fall and winter finally approaches, and as we adjust to our winter routine of spending less and less time outside, I wanted to share with you a special interior green space here in the city we can all enjoy. Below are pictures from the Ford Foundation Atrium, which is located between 42nd and 43rd Streets just west of First Avenue. Built from 1963-67, this interior garden space is one of the most popular green atriums here in New York City, and rightfully so. When you enter this green oasis you can't help be amazed by the tropical plants of all shapes and sizes that stand before you. As you follow the choreography of the pathways you find yourself eventually surrounded by these trees and shrubs, taking in the good air, and at peace thanks to the soft sound of the water feature in the center. The atrium is open to the public from 10-4 on business days and if you have never been, it is a visit that you should treat yourself to very soon. Even yesterday, on such a dreary day here in the city, my coworker and I couldn't help but feel inspired and energized after our trip through the atrium.
Different kinds of Ficus trees that have been there for years are now well established and reaching up 20+ feet into the vaulted ceiling that goes up the entire height of the building.
Below the larger trees the sloped beds are loaded with tropical shrubs like Schefflera arboricola with it's rounded palmately compound leaves, and groundcovers like Trandescantia with striking purple on the undersides of their silver-striped leaves, just to name a few. Variegated plants are incorporated too, like the arrowhead vine (Syngonium podophyllum) to provide additional texture to the planting beds on a year-round basis. With enough plants to maintain decent humidity in the atrium there were even a number of different ferns that I was thrilled to come across.
As we strolled through my coworker and I had to marvel at how brilliantly the atrium was laid out so that it was visible and enjoyable to all those in the offices up above. A man and woman were sitting on one of the paths having an afternoon debriefing and certainly we thought they had found the perfect setting for their little meeting.
In addition to all the levels and layers on the ground floor there is a mezzanine that had large trees and shrubs in it, as well as many hanging plants that cascade down to welcome you when you enter from 43rd Street.
And even though most of the plants in the atrium are tropical plants known for their foliage, I was able to find a few wonderful flowers to educate my colleague about. Above is a tropical shrub or tree botanically known as a Calliandra. Not surprisingly the common name of this tropical shrub is known as either powderpuff or flame bush. There were also camellias in bud and a few already putting out their multi-petaled winter blossoms. Down by the water feature in the center I found a gardenia that still had a number of their intensely fragrant flowers on it, and I tell you, I could stand there and smell the gardenias all day they are so amazing. So, next time you are over on the east side around 42nd or 43rd Street, treat yourself to a walk through the Ford Foundation Atrium. I am sure you will be pleasantly surprised. And lastly, as always, keep in touch with HSNY and become a member as I hope to lead a tour or two of the atrium, and perhaps others, in the upcoming months.

Plant ID: Gaultheria procumbens

Walking in the Flower District the other day preparing for an event I was impressed to find many vendors selling Gaultheria procumbens, commonly called checkerberry or wintergreen. Wintergreen is a North American native, and it is very important to try and incorporate as many native species into our gardens as possible. These plants are used to the climate here in the northeast and you do not have to fear them becoming invasive as some introduced species from other continents may become over time. Wintergreen is cold hardy in USDA Zones 4-8. It prefers full sun but can tolerate part shade. This plant does best in rich organic soil, so do not hesitate to incorporate a lot of compost when planting. As with many perennials, younger plants are more resilient and can often adapt more quickly to their new environment compared to much larger, older specimens. Last summer I was able to get to know wintergreen first-hand visiting and working in a number of gardens and sanctuaries up north in Massachusetts and in it's natural environment these plants perform best in a soil that is kept moist on a regular basis. Individual plants of Gaultheria procumbens will only get to about 6" tall, but over time they can spread up to 3' wide, so they make for a tremendous groundcover. Pale pink flowers in summer will produce these red, waxy berries that will persist through the winter. In addition the foliage will turn an attractive red in fall. As the name might suggest, this is the plant from which wintergreen oil is derived. It is the berries that are processed to make this essential oil that is used as a liniment for muscle and joint problems. Next time you see this plant, or better yet when you go to purchase one for your own garden, crush one of the leaves in your fingers and the scent I'm sure will raise your eyebrows and enlighten your senses.

Monday, November 12, 2007

Events This Week at HSNY

The following event will be held at The Horticultural Society of New York, 148 W. 37th Street, 13th Floor. To RSVP contact Fiona Luhrmann at 212 757-0915 ext.100 or

Fun with Fall Flowers: A demonstration class with Robb Moss
Thursday, November 15, 2007, 6:00 – 7:30pm
Free for HSNY members, $10 for nonmembers
Join Robb Moss, co-owner of the New York Studio of Floral Arts, for a demonstration class about fun fall arrangements you can make for the holidays. You will also learn more about how HSNY members will get ongoing discounts at Robb’s floral studio right in the heart of the Flower District.

Thursday, November 8, 2007

Figs (continued)

(photographs of a Ficus carica in Astoria, Queens, pruned and tied and ready to be wrapped for the winter)

I have a question for you regarding a fig tree, about 5+ feet tall, planted this spring: When should it be pruned, now or in the spring? I believe here in Peekskill it should be wrapped with burlap in the winter, but when??

Regarding the fig, those are some excellent questions. I did post a blog entry about figs in late October and if you click on the link here you will find that. As far as wrapping you definitely do want to wrap the tree if you are up in Peekskill, and now is a good time to do that. As far as how to wrap it, that is a bit trickier and I admit to you I am still learning. I live in a mostly Greek part of Queens and what I saw last weekend really intrigued me.

Every winter I see that people have wrapped their figs so tightly that they appear extremely tall and narrow, like a tightly bound bundle only a foot or two in diameter but easily 8 or 10 feet tall. Luckily during my walk on Sunday I got a little more insight into the process. I came across a tree that had been pruned and tied, but not yet wrapped, so I could better understand the process of winterizing these warmer-climate-loving trees. The owner had cut each branch back very hard so there were only a few (2-3’) feet of growth coming from the main trunk of the tree. What he was left with was bare branches; the thin branches towards the tips of the tree with lots of foliage and even some fruit he simply chopped off and got rid of. Then he had taken each branch and slowly forced it so that it was held right against the trunk pointed upwards. Now, I was confused as to how he was able to bend all the branches without them cracking or breaking, but unfortunately the owner had gone inside and I missed my opportunity to ask him. With all the branches tied to the trunk with a ton of rope and twine, I assumed the next step was to wrap it in a tarp and leave it to rest through the winter. Before receiving this visual insight I always thought that you wanted to prune in the spring and not prune them heavily in the fall, but apparently I still have some things to learn about over-wintering figs in New York. Obviously there are still some questions to be answered and I hope during a walk home soon I can run into another neighbor wrapping their fig so I can clear up a few things. When I do I will definitely be in touch.

Iris (continued)

(photograph of Iris 'Cherokee Heritage' taken at NYBG late May, 2005)

Thank you for your prompt response, Alex. I grew up in Michigan. So know iris can grow in the cold. I will see if I can find out about cold hardiness. One more question. The way you describe planting them is exactly the way we would do it out here. What about the rhizomes
freezing when they're so shallow, particularly the first year? Do I mulch? And, if so, how much and with what?

I did a little more research and you are right, it doesn't seem like there is a question of whether the iris are cold hardiness enough. As far as the big rhizomatous iris (German bearded iris, etc.) I've found that they are quite durable even though they are right at the surface of the soil. Up at the New York Botanical Garden where I was a student and worker for two years they have a tremendous spread of bearded iris and I do not remember mulching them at all. They are in an area with a lot of gravel to provide maximum drainage and that is certainly important. I've done some research and what I've found seems to make sense. Do not mulch with leaves, woodchips, or anything equally organic that might hold too much moisture and promote rot. If your new home stays evenly cold through the winter and there is reliable snow cover then I do not think you have to mulch. If you fear that there might be a lot of freezing and thawing spells that might disrupt the iris then I would recommend laying down a single layer of evergreen boughs to provide a light, airy layer of protection. Obviously it would have been more ideal to get them transplanted with enough time to establish some roots in their new home before winter, but hey, some times we just do the best we can given the circumstances.

Tuesday, November 6, 2007

Moving Iris Corms Upstate?


We are planning a move to upstate NY, around Utica. I am bringing some iris corms from Oregon and am wondering how to take care of them and grow them in NY's climate. Any ideas? resources? Thank you.

Thanks for writing. Since you are moving from Oregon, where the climate is milder for the most part, it might be worth double-checking that your corms are going to be cold hardy to zone 5 or even colder, zone 4. If you know the species of iris you are bringing I would imagine most references will be able to tell you their cold hardiness. That being said, I would simply get them in the ground when you get here. As long as you can pierce the ground I would plant your corms about 4" down in a spot with ample sun and soil that is well draining. If you are dealing with larger bearded iris then those rhizomes need to be planted much shallower, with the top 1/3 or 1/2 of the rhizome above ground. Again, it might be worth checking the cold hardiness first. Either way, planted in the fall your iris should be able to establish enough of a root system to perform well for you next summer. As far as references to use, the American Horticultural Society puts out a number of books through DK publishing that I consider excellent reference books across the boards. They are even getting more specific with regional books and they do have one specifically on the northeast. Otherwise, when you get here ask you local garden center what books they use as references. Regarding the internet I like a website called and can easily spend days reading about everyone's experiences, successes, etc.

In related news, I will be teaching an informal demonstration class on planting bulbs in containers tonight at the HSNY headquarters from 6-7:30. I will be discussing planting bulbs both indoors and out and there will be a little hands-on demontration towards the end. This program is free for HSNY members and $10 for nonmembers.