Wednesday, October 31, 2007

Alternative to Dwarf Alberta Spruce in Containers

I recently ran into a friend who had a good question about evergreen plants for containers. Outside of where she works in Brooklyn, a small retail shop, they have two large pots that are about 16" or 18" inches in diameter. She described the small trees planted in them at present and I was able to assess that they were dwarf Alberta spruce, Picea glauca 'Conica'. Dwarf Alberta spruce are slow-growing, short-needles evergreens that grow in a very conical habit and are quite popular for use in containers. If you see one in passing you might say it looks like a perfectly miniature Christmas tree. Liz was concerned because they were developing many brown patches and beginning to look pretty rough. She was wondering how she might fix the situation and if the trees will bounce back. I asked about sunlight to the area where the pots are situated and Liz said that there is partial sun and definitely some shade. Spruces of different shapes and sizes are attractive evergreens because of their sturdy needles, dense growth habit, and slow rate of growth. The photo below is a small containerized spruce (not a dwarf Alberta) that I saw in the Flower District on 28th Street.
The catch with spruce is that they need to be grown in a full sun application to do best. By this I mean they need at least 4-6 hours, if not more, of direct sun daily. If they are in too much shade, they begin to thin themselves out from the bottom up so that they can have the most efficient amount of needles working for the relative sunlight they receive. Unfortunately most coniferous trees, such as spruce, do not rejuvenate and put out new growth from their lower branches like herbaceous or broadleaf evergreens might. Therefore I recommended to Liz that the trees be pulled out of the containers and planted somewhere where they will get more direct sunlight. She had an idea as to where they could go and said she would move them. I recommended that she prune out the dead branches, that they would most likely not produce needles again, and hope that over time as the remaining branches grow and spread that they might fill in the holes that are presently there. However, Liz then had one last question. What can I plant in the containers that will do better?

A reliable option, and a selection of plants typically easy to find in the city, various hollies (Ilex) are excellent plants to use in containers with part shade. This is a containerized Japanese holly (Ilex crenata) I found while down on 28th Street that I think might be a good option.

It will grow a few inches a year and will keep that overall shape that is rather conical. Eventually it will want to be replanted to a garden, but for a few years it would hold up in an adequate sized pot with ample drainage. If you wanted an even slower grower, you might also consider boxwood (Buxus sp.).
Boxwood and Japanese holly may look alike, but there is one way of telling the two apart. Take a close look at the small rounded leaves produced by each broadleaf evergreen shrub. If you touch the margin, or edge, of the Japanese holly leaf you will feel a very slight serration, while the margin of the boxwood leaf is always completely smooth. Boxwood are slower growers compared to most hollies but it will do just as well in a container in part sun or shade. In either case you could plant these shrubs in the pots out front of your work for some instant structure and then plant annuals or vines around the edge for an extra added shot of color.

There are other options as well and we can discuss those further. There are larger leafed hollies that hold up well in containers in the city, but eventually they will get large and need to be planted in the ground.
Variegated plants, with two-tone leaves, are attractive because they provide different color and texture within one plant, but it is helpful to know that variegated plants often require more sun. If you think about it, the white, or light parts of the leaves do not have as much chlorophyll in them as an all-green leaf might, so they often need more sun to efficiently photosynthesize and grow. Grasses can be great too, especially for their potential fall color, and again, I am more than happy to discuss some of those options as well. Best of Luck.

Daisies Growing Out of a Succulent?

(This is a photograph I took of a Delosperma species growing amidst various Sedum and other succulents in a green wall application in Williamsburg, Brooklyn)

I have a plant on my terrace, looks sort of like an artichoke. For the first time since I've had this plant, it budded out and from the bud was born a perfectly beautiful daisy?
The other parts of this plant have sprouted their daisies as well and I would like to know what this kinds of succulent brings forth daisies?

Believe it or not, a succulent that has a showy, daisy-like flower is not that unheard of at all. Because they are used to growing in challenging environments, such as arid and exposed deserts, it makes sense from a survival standpoint that cacti and succulents are very compact, often drought tolerant, and otherwise durable plants in the landscape. What people may not automatically think about is that because their natural environment may lack an over abundance of pollinators, cacti and succulents typically have very bright and showy flowers to be able to attract their respective pollinators from great distances. One such example is a plant botanically known as Delosperma, or ice plants as some refer to them. Delosperma are succulents that do most of their nutrient storage and water retention in their large fleshy leaves and they appear very much like your typical succulent. Once established the plants do flower and their blooms are wonderfully showy daisy-like flowers that can range from pink to purple. Now, I am not sure if the plant that you have written me about is definitely a Delosperma, but if you are able to email me a picture of it, please do and hopefully we can identify it to a more specific genus and/or species.

Growing Figs in Brooklyn?

Every week i see beautiful fig plants at the green market, and am tempted to plant several in my back yard (in Brooklyn). I know they are not really frost tolerant, and remember reading Joan Dye Gussow describing how she wraps hers in burlap every autumn (but she lives on the banks of the Hudson). I also remember some figs in the back yard of a house here in my neighborhood, which i was told had been planted MANY years ago from plants or cuttings brought over from Italy. the garden had been neglected for years, but the figs had flourished, without bundling up, i assume. So, what do you think about figs in WIlliamsburg? i have a small stone patio, which will hold some heat. Can you recommend any other edible perennials for the urban gardener? I was thinking about fruit trees, but wouldn't be able to, or want to, spray...
also, a totally separate question.

I've been reading about the decline of common songbirds in this country, and wonder what I could plant to feed/shelter the birds. I have some big weeds that grow clusters of dark purple berries that the birds seem to dig, but the plants aren't that nice. I'd rather choose a perennial/shrub/tree than keep working around the big weeds.

Your question about the fig is an excellent one. The common fig is botanically known as Ficus carica. This shrub or small tree is native to western Asia and the eastern Mediterranean region and has been cultivated for thousands of years. A number of references describe the fig as only being hardy to zone 8 or warmer, which makes it an unlikely candidate for our colder 6b or 7a conditions here in the city. However, that being said, in my neighborhood of Astoria, Queens, where there is a substantial Mediterranean population, there are figs being grown everywhere!

I would say that you should definitely try and grow one in your backyard in Williamsburg. Well, I should add that planted in the ground I think they might do fine, but in containers I would not recommend figs because their roots will freeze through and really suffer. Figs grown in the city benefit from a sheltered sunny location in a backyard or protected community garden. They thrive on long warm summers in full sun and a dry atmosphere, so for the most part our city summers are perfect for them. In the winter you will need to wrap it, and a couple layers of burlap or a breathable tarp over the entire tree is necessary. In Queens I even see people wrap them in those standard blue all-purpose tarps, which I fear will suffocate the winterized tree, but every spring I am amazed at how the trees come back and leaf out bigger and better than before. Not to mention the fruits do turn out to be delicious. Now, it is possible that some of those trees in my neighborhood have been there for many years and originated as cuttings from overseas, but I would say that if you can find a small specimen then you should have a good chance of success as well. As a general rule of thumb for all trees, they are most resilient in their youth and slowly become less-so as they mature. Therefore, you should be able to plant and care for a small tree and it should be able to adapt to your environment well enough that it will be around for years of enjoyment.

As for the other question about the birds, there are plenty of shrubs that produce edible fruit that songbirds will love. The plant with berries that you are describing is most likely a weed called pokeweed (Phytolacca Americana) and it can certainly become a late summer nuisance. Shrubs that you might consider to plant for the birds would include blueberry (Vaccinium), serviceberry (Amelanchier), dogwood (Cornus), snowberry (Symphoricarpos), blackberry and/or raspberry (Rubus), and many many more. If you are thinking more in terms of trees then there are plenty of apples (Malus) and cherries (Prunus) you might consider. Here in our library we have a great book called Bird Gardens, a 21st-Century Gardening Series publication by Brooklyn Botanic Garden, and it would be a perfect book to give you plant suggestions based on your garden's orientation and exposure.

Tuesday, October 23, 2007

How to Care for a Bromeliad?

(Neoregelia is a member of the Bromeliaceae family that we grow here at HSNY Headquarters)

I have a Bromelia plant and would like any care instructions you could provide. Do I water it at the top of the leaves and let it funnel down as I have been told. The water seems to accumulate and I fear will rot the leaves. How close to the leaves should the dirt go? It does not get direct sunlight is that okay? The flower fell off, will it grow another?

Bromelias and other members of the Bromeliaceae family, collectively called bromeliads, can be pretty easy to care for. As you know, the leaves emerge from a central rosette and create a bit of a cup. It is true that you want to water your bromeliad by pouring water into that cup. In their natural habitat, bromeliads grow at elevations up to 6,000 feet and are either epiphytic (meaning they grow on other plants) or they are terrestrial (meaning they grow in the ground). For this reason, they take in the majority of their water through the “cup” which serves as a water reservoir. During the summer months when the plant is most active you will see that the center will dry out and will need to be refilled frequently. You always want to keep some water in the cup, but during the winter months when the plant is less active you will realize it does not take it up nearly as quickly. Do not worry about rotting the leaves, they are tough. As for the mix it is potted in, you can water that occasionally as well, maybe once a week or so. The mix is more to anchor the plant in place, but if saturated, that can rot the base of the plant and you want to avoid that. Bromeliads love humidity so you may choose to have a layer of stones in your saucer so that excess water can evaporate immediately around the plant without the plant actually sitting in water. As far as the soil level, in some cases the potting mix is right up to where the plant flares out, in other cases there might be a little more of a stalk. This can vary as long as the plant is properly anchored in place and the mix drains freely. If it does not get direct sunlight, at least provide it with as much bright light as you can. I do not recommend bromeliads for shady situations. Finally, regarding the flower, you are going to continue to grow your bromeliad and you are going to watch out for a new growth from the base. A new side-shoot should eventually emerge, and grow into a tall plant of its own. Eventually this side-shoot, called a “pup” will grow to be large enough that it will produce another flower.

Thursday, October 18, 2007

Recent Press: GreenBranches Learning Gardens

This morning Kate Chura, HSNY Vice President, passed on to me these fabulous articles written recently about our GreenBranches Learning Gardens. Please read and enjoy the following articles and be sure to click on the accompanying photography.

To read the article that appeared on, click here.

To read the LJ Insider blog entry by author Raya Kuzyk, click here.

And also, thank you to all the HSNY members as well as members of the HSNY Board of Directors who came last evening to our 105th Annual Meeting of The Horticultural Society of New York. It was a pleasure to give you updates and insights into all of our various community outreach programs, services, and resources. We loved having you all here, including of course our guest speaker, Deirdre Larkin, Associate Manager of Horticulture at the Cloisters branch of the Metropolitan Museum of Art, another tremendously faithful HSNY member. We were honored and thrilled to have Deirdre here to discuss and share with us the intricacies and brilliance of the Cloisters gardens as well as her visions for moving "Forward into the Past". So, again, thank you all for coming last night and supporting HSNY!

Tuesday, October 16, 2007

Annual Meeting Reminder

The Horticultural Society of New York enhances our City's environmental and cultural life by providing unique educational, vocational, and therapeutic outreach programs, library resources, and art exhibitions.

This is a reminder to all of our important and supportive HSNY Members that the Annual Meeting of The Horticultural Society of New York is happening tomorrow evening, October 17, 2007, starting at 5:00pm.

Come and enjoy updates from all of our different departments, including Horticulture, the HSNY Library, Art Exhibitions, and Special Events. Of course you will also hear the latest from our unique community outreach programs including AppleSeed, GreenTeam, Greenhouse, and GreenBranches. Following the HSNY presentations we are thrilled to have Deirdre Larkin, Associate Horticulture Manager at the Cloisters, as our guest speaker. Important member-based voting will take place so please come and make your voice heard. As a thank you, the first 50 members in attendance will receive a complimentary plant to take home.

It is going to be a fabulous evening and I hope to see all of you here. The meeting will begin at 5:oopm here at our headquarters at 148 West 37th Street, 13th Floor, New York, NY 10018. If you have not yet RSVP'd, or if you are interested in taking out an HSNY membership so that you can attend and help support our organization, please contact Adam Gwon, HSNY Membership Coordinator at (212) 757-0915 ext.121 or

Monday, October 15, 2007

Plant ID: Rhamnus cathartica

I have a large row of bushes/shrubs that are at least 10 feet tall and I haven't been able to identify them. They seem to be common in my area (central New York) since I frequently go for walks around the Erie Canal and see them everywhere in the wild. I would like to plant some more since some of the hedgerow has been taken over by vines and the bushes have died. The leaves on the branches are directly across from each other and each leaf has jagged edges are are oval shaped with a point on the end opposite the stem. The veins on the leaf start down at the base of the stem and go up following the shape of the leaf and the veins are identical on each side of the leaf. In the fall this bush produces berries that are black/deep purple in color. I have included pictures. Could you please help me in identifying this? I've done a search on the internet and haven't been able to come up with anything.
Thank you for writing. The shrub you are trying to identify is Rhamnus cathartica, commonly known as common buckthorn. This shrub is native to Europe and western and northern Asia. As you have discovered on your walks, this large shrub has a dense, rounded growth habit and can get as large as 18’ high and wide. The glossy dark green foliage is 1 ½” -3” long and almost as wide, with an acute tip and finely serrated edges. In the fall common buckthorn bears in clusters these ¼” black fruits, technically called berry-like drupes. Common buckthorn is cold hardy in Zones 2-7, which means it can live most anywhere between New York City and colder points much further north.

Even though the shrub has some attractive characteristics, I must deter you from searching for or planting this shrub as it is considered invasive. According to the USDA website, common buckthorn is considered invasive and/or banned in Connecticut, Massachusetts, New Hampshire, and Vermont. I was not able to find information pertaining to the status of this plant in New York, so I would go ahead and steer clear of it to avoid potential fines or danger to your local environment. I am not sure how familiar you are with invasive plants, but here is a little more information as to how this shrub has become classified as such.

Over the past centuries, plants from other continents have been introduced to North American landscapes because they were considered beautiful and viable in our climate zone. Common buckthorn, with its dense habit, glossy leaf, and black fruit, is a perfect example. Norway maples (Acer platanoides), burning bush (Euonymus alatus), and purple loosestrife (Lythrum salicaria) are other examples of invasive species in the Northeast. They were planted, they did well, continued to grow and produce flower and fruit, and spread throughout the landscape. The problem, however, was that people did not think about how they might have to eventually control the plant’s populations. Because it is from another part of the world, predators and/or insects that feed or do damage to the plant do not exist, nor are there other plants that grow as quickly and aggressively to naturally compete with the buckthorn. This is how introduced plants can then become considered invasive. The plant was left loose in the wild for long enough and continued to spread, and now it is overtaking native plants and natural habitats. This leaves us having to turn to nature conservancies and habitat restoration advocates to come in an attempt to undo decades of wrong-doing. And I can speak from personal experience that it is the most admirable work and yet the most overwhelming and greatest challenge ahead of us as horticulturists and stewards of the land. Just in your area think about how much invasive buckthorn there must be. We must always be careful of introducing non-native plants. It is always a better practice to choose native alternatives instead.

That being said, are you familiar with viburnums? There are many different kinds of viburnum, most of which are North American natives, that can be planted in a row to create a nice full hedge. Depending on the specific species, viburnums may have fabulous spring flowers that can be very sweet and fragrant, excellent variation of leaf shape and size, interesting fruit-set in the fall, intense fall color, or all the above.

Thursday, October 11, 2007

Plant ID: Lantana camara

(Lantana camara in front of the Javits Center, NYC. Photography by Alex Feleppa, 2007)

There's a lovely flower in the pots outside the Javits Center and I'd love to know what it is. Hard to describe something so visual, I know, but here goes:
It's a cluster of small flowers, making up one large half-round head. The smaller flowers are shaped like Alyssum – four distinct petals with a center. The large head is the interesting part, though. It consists of a center grouping of yellow, with an outer ring of magenta. The colors are like Lantana, but more intense, and these component flower petals aren't sharply defined enough. And it makes berries! Fully-round, dark purple, and sort of in grapelike clusters.
If it weren't for the berries, I'd think it was a variety of Lantana or Alyssum, but they don't make berries, do they? I'm stumped. Looking forward to hearing from you.

I finally took a walk over to the Javitz today on my lunch break. I found the mystery plant, and its mystery fruit, and you’re first instinct was absolutely right – it’s a Lantana!

Lantana camara is commonly called lantana or yellow sage. Native to the West Indies and Central America this plant requires warmer winters so we can only enjoy it as an annual here in New York. However, what a fabulous annual it is. Not only does lantana tolerate more sandy and/or nutrient-poor soils, some experienced horticulturists swear that the plant actually performs better in these conditions. Either way I love to use lantana, whether spilling out of containers or adding extra "pop" to annual or perennial garden beds. The long, sturdy stems with pom-poms of hot-colored flower clusters are sensational. I also like the fruity, almost musky fragrance of the crushed foliage, but some may disagree with me on that. An extra added bonus is that once established in your garden it can prove to be a bit more drought tolerant than other annuals we typically plant.

The pictures above are ones I took of the fruit-set you were describing to me. I am so glad you brought that to my attention. I admit, you had me stumped too! Lantana has long been one of my favorite annuals since I began my career in horticulture, but I had never seen it set fruit. I would guess these plants were planted early on in spring since the leaves are as large as they are. Obviously during the summer the flowers were pollinated, by butterflies, and it has been a long and hot enough since then that the plants were able to produce their fruit. In each of the fruit is a viable seed, but I am not sure how easy it is to propagate them. I certainly am tempted to grab a few of the fruit clusters though and see if I can get the seeds to grow.

Annuals with Style by Michael A. Ruggiero, Taunton Press, 2002.

Roots and Winter Protection

(photo of Phyllostachys aureosulcata 'Spectabilis')

I have just moved to New York from Boston where I spent the last 4 years. I am originally from London, UK. We have an 18th floor north facing balcony which I am gradually buying plants for. Yesterday I bought a bamboo from 28th Street. I don’t know what species it is but it is tall and has yellow stems – maybe it is Phyllostachys aureosulcata? It is fantastically root bound. I have taken it out of its pot and am soaking its roots before repotting it tomorrow. I doubt if I’ll be able to make any headway unraveling the roots but I will try. If I have no luck is it OK to cut some of them to free them from going round and round for ever? Also will it need winter protection? I had some luck in Boston on a 28th floor balcony wrapping plants in burlap and Frost Protek.

I have also bought a Euonymus Manhatten which I am told needs more direct sunshine than I can provide, but I am ignoring this fact and hoping for the best. The balcony is very light. Will this need to be wrapped up when the temperature falls? Both are in 17” pots.

Perhaps you have already dealt with the bamboo, but I am sure it is fine if you have to cut some of the roots that are too difficult to deal with. As with shoot pruning, root pruning is going to promote the growth of new root tissue so a little pruning is no problem. It is more important to train new roots downward into fresh soil than allowing the existing roots to potentially girdle the plant. Not to mention bamboo is such a tough and aggressive plant that I think you would have to cut off a ton of roots before you actually begin to stress the plant out. From my own experience I have lifted and divided a number of bamboo, complete with some root pruning, and they only seem to come back stronger and healthier. As for the winter protection, if you are familiar with the practice, then I would go ahead and do it to be safe. I hope that you do have Phyllostachys aureosulcata as it is more wind tolerant and more cold tolerant than Phyllostachys aurea. According to a few references here in the HSNY Library Phyllostachys aureosulcata is only hardy to zone 6 so there is no question the roots would appreciate a little extra protection.

As for the Manhattan euonymus, I would definitely wrap it. The larger foliage and softer stems (compared to the bamboo) will take more of a hit from the winter weather. According to references Euonymus kiautschovicus 'Manhattan' is only hardy to zone 6 as well, so again, the roots will appreciate the added insulation. As for the light issue, if the shrub drops some of its lower, internal leaves next year you will know it is most likely because the shrub is not getting enough sun. But I’m with you. Give it a shot and see what happens. I’ll keep my fingers crossed for you!

Wednesday, October 3, 2007

HSNY Green Wall and Open House New York

Have you been to the The Horticultural Society of New York recently to see the additions to our own indoor Green Wall? Thanks to a generous donation from our friends at Landcraft Environmentals we have a number of new plants growing and acclimating well to their new home up above 37th Street. Landcraft Environmentals is a wholesale nursery on Long Island that grows an unbelievable spread of plant material. You can find their tropical, perennial, and other plants sold at Chelsea Garden Center and various shops throughout the Flower District.

Consider coming and enjoying our new headquarters as part of Open House New York. Designed by Marpillero Pollak Architects, the new HSNY headquarters includes a sensational art exhibition gallery, the most unique horticultural library of it's kind in Manhattan, meeting space, office space, and a welcoming environment full of light and plants for all the public to enjoy. As part of Open House New York, HSNY will be open on Saturday, October 6, 2007 from 12 to 3pm. For more information visit the Open House New York website here.

Monday, October 1, 2007

Plant ID: Mandevilla x amoena

My friend was given this plant but is unsure of what it is called.
Can you please tell me what it is and how to overwinter it here in Michigan?

The plant your friend was given is called a mandevilla (Mandevilla x amoena). Native to Brazil, this climbing vine is a hybridized cross of Mandevilla amabilis and Mendevilla spendens. Because of its tropical origin, the plant cannot tolerate winter temperatures below 55 or 60 degrees. Therefore, the only option to successfully overwinter the plant in Michigan is to bring it inside. Keep it in an area of bright light, but be careful that it is not too close to a hot, dry radiator. Continue to water it as you have been, and as winter comes you can ease up and water more sparingly. When overwintering tropicals inside, I like to use below the pot a glazed saucer with a layer of stones or pebbles in it. This way excess water that is in the saucer can evaporate and provide a little extra humidity during the dry winter months without running the risk of rotting the roots of the plant. You can also mist the foliage if you feel the plant is getting too dry. A reference book I have says to cut the plant back to keep it bushy and promote next years flower, but I might recommend against that. I had one in my home years ago that I cut back hard this time of year and it seemed like forever before it got to be as full as it was. I prefer to stake it well and let it continue to climb. Through the winter the vine should continue to grow and put out new foliage, but do not expect much in the way of flowers until next summer. When you move it outside next spring check on the roots as it may be ready to be repotted.
Reference: Indoor Plants: The Essential Guide to Choosing and Caring for Houseplants by Jane Courtier and Graham Clarke, Reader's Digest, 1997.