Thursday, November 29, 2007

Plant ID: Lysimachia clethroides (A Discussion on the Topic of Invasive Plants)

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 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, August 13, 2007

Wildflowers of Colorado

During a recent trip to the western half of Colorado I was fortunate to find myself amidst fields of wildflowers on a number of occasions. Even though I was able to identify most plants to genus right away, many of these plant species where new discoveries for me. I thought I would post some of my photographs and share with you some of my findings, along with additional information found in Don Mammoser's Wildflowers of Colorado Field Guide, 2007. Keep in mind that these plants were situated atop mountainsides at 10,500 feet above sea level and may not be suitable for gardens here in New York City.
Mertensia ciliata is commonly called tall fringed bluebells. As confirmed by Mammoser, these bluebells prefer wet mountainous areas and form dense clumps that stand 3-4' tall. You may recognize this plant as being related to Virginia bluebells (Mertensia virginica), the spring blooming native found here in the northeast. Whereas Virginia bluebells bloom early and begin to die back by this time of year, these tall fringed bluebells were blooming late into July before the arrival of monsoon season in early August. The genus Mertensia is named after the German botanist Franz Mertens.

Pedicularis racemosa is commonly called sickle-leaved lousewort. This plant amazed me because the tubular curved petal at the top of each flower was like nothing I had ever seen before. I learned that this plant is a member of the snapdragon family, Scophulariaceae. The plant and flower spike stood about 18-24" tall. According to Mammoser there is another species, Pedicularis groenlandica, that is commonly called elephant's head, and has an even more pronounced "snout" of a petal. Just the same I was thrilled to find this less common species along a trail in Grand Mesa National Forest.

Identifying yellow or orange daisy-like flowers in the wild can often be frustrating because of the multitude of possible candidates. Here I believe I have captured three phases of Hymenoxys hoopesii, commonly called orange sneezeweed, from a budded to a fully open flower. Orange sneezeweed stands in clumps from 2-4' tall and attract butterflies, bees, and moths. As a member of the aster family, Asteraceae, you should know that each flower is in fact a collection of many flowers. Here many "disk" and "ray" flowers are situated together to give the impression that you are looking at a single flower when in fact you are looking at a large clump of individual flowers. To help explain this morphological characteristic, think about a sunflower, another member of the Asteraceae family. Eventually the center of that sunflower blossom produces many sunflower seeds, right? That is because the individual disk flowers in the center have each been pollinated and gone to seed. Take a look at this cross section of a flower in the Asteraceae family and hopefully that will help drive this little morphology lesson home. Do you see the individual flowers lined up next to each other?

Chamerion angustifolium is commonly called fireweed. The seeds of these native wildflowers are easily dispersed by wind and are known to be one of the first plants to grow after a forest fire, hence the name (Mammoser, 2007). Growing in large masses that stand 4-6' tall these plants are strikingly beautiful whether near or far. Each flower spike comfortably stands a healthy 12" above the upright herbaceous shrub of narrow, willow-like green leaves.

Erigeron speciosus is commonly called Aspen fleabane or showy fleabane. Standing 12-24" tall with light purple flowers typically 1-2" in diameter, this plant is also a member of the Asteraceae family. Native to foothills, aspen groves, and meadows along the forest edge in western Colorado, I seemed to find these on every trail. The name speciosus means "showy" and refers to the blossoms that stand atop long stems rising from the basal rosette of foliage. showy fleabane is a host plant for the Northern Checkerspot butterfly (Mammoser, 2007).
Geranium richardsonii is commonly called Richardson geranium. This perennial geranium grows both in low and high elevations, from New Mexico north to Colorado and up to the Canadian Rockies. The white petals have subtle purple venation to them and are quite delicate and beautiful when looked at up close, and sometimes the entire flower can have a soft pink hue. According to John Richardson was a surgeon and naturalist who lived and studied in the arctic and Canada in the 19th Century, but it was his fellow explorer, Thomas Drummond, who collected the first specimen in 1826 or 1827.

Of course, it wouldn't be Colorado without Aquilegia caerulea, commonly called the Colorado blue columbine. On the rocky slopes where I found these members of the buttercup family, Ranunculaceae, they were only standing 8-12" tall. A state protected species, Colorado blue columbines are an important nectar source for several hummingbird species in Colorado (Mammoser, 2007). Like other forms of Aquilegia, this species is known for its ability to self-seed itself throughout the challenging landscape.
Campanula rotundifolia is commonly called harebell. Do not let this picture fool you, these members of the bellflower family, Campanulaceae, only stand about 6-8" tall. The name bellflower refers to how the 5 blue/purple petals are fused together to create a bell shape. The flowers themselves are about 3/4" in size. Able to grow anywhere there is moisture and full sun, you can find these little plants mostly growing in rocky outcroppings and prairies. But do not walk too fast, or you might very well pass them by without even knowing.

Lastly, a representative from the genus Delphinium. Unsure whether it is Delphinium nelsonii or Delphinium barbeyi, members of this genus are commonly called larkspur. With a base of large lobed leaves with pointed tips, tall spikes of intense purple flowers shoot up making the plant stand 4-6' tall. Even though these plants put on a real show in the moist meadows and forest openings where they live, they are disliked by ranchers in western Colorado because they are toxic to livestock. According to Mammoser, "most of the plant parts contain poisonous alkaloids that can be fatal if ingested", and he even urges humans not to touch the plant. This, of course, I read after spending an afternoon studying and touching this plant, but luckily I did not fall victim to any such illness.

Thursday, July 19, 2007


I had a meeting with the Parks Department that had me out to Flushing Meadows Park in Queens today. It was the first time I had ever been so close to this phenomenal public sculpture. Of course, as a New Yorker I grew up driving by this old site of the 1964-1965 World's Fair when my parents and I would come into the city for a museum day or field trip. Not to mention I think it was in the opening credits of a standard kids show like Sesame Street, so it is forever ingrained in my brain as a classic New York City icon.
The massive stainless steel globe stands 140 feet tall and weighs 900,000 pounds, including the 100-ton tripod base. The theme of the '64/'65 World's Fair was "Peace Through Understanding" and the Unisphere was conceived and commissioned to be the main symbol of the fair. It was designed by landscape architect Gilmore D. Clark and built by the United States Steel Corporation.
It's a pretty brilliant testimonial to New York City as a place where so many worlds come together.

Friday, July 13, 2007

In Bloom This Week in NYC

Campsis radicans is commonly called trumpet creeper.
Trumpet creeper is a wonderfully vigorous climber that does very well in New York. Their glossy green compound leaves of 7-11 toothed leaflets can quickly cover whatever structure you choose to grow them on. Botanically referred to as "terminal cymes", flowers are produced in clusters at the outer-most tips of the new stems and foliage. As the bright red tubular flowers suggest, this vine is pollinated by hummingbirds. Trumpet creeper performs best planted in full sun. It thrives in moist, well-drained soil, but I have seen this plant adapt to a wide range of soil conditions. We have used this plant in a number of our GreenBranches Learning Gardens and it is always a fan favorite. Once established you can prune them back pretty freely in spring. Trumpet creeper is hardy in Zones 5-9 and can grow to 30' and beyond.
Hibiscus syriacus (cultivar unknown) is commonly called rose of Sharon.
Rose of Sharon is commonly found as an upright, rangy shrub (above), but sometimes is grown and trained into a tree form as was done with the specimen below. Rose of Sharon is an interesting shrub in that you typically find that people either love it or hate it. The deciduous branches become covered with coarsely toothed 4" leaves that are dark green. A positive characteristic is that these shrubs bloom from mid- to late-summer and the flower can be quite showy. A negative is that rose of Sharon is known to seed itself quite freely. Therefore, having one on your property, or even one nearby on your neighbors property, may very well mean that you have extra weeding responsibilities to prevent the woody seedlings from taking hold. Native from China to India these shrubs can grow to 10' tall by 6' wide, and are hardy in Zones 5-9. There are so many cultivars sold in the trade these days you can find rose of Sharon in a number of hot and cool colors. Plant them in full sun for optimal flower.

Hydrangea macrophylla (cultivar unknown) is commonly called bigleaf hydrangea. I could easily spend days talking about the many cultivars of bigleaf hydrangea. These popular deciduous shrubs are divided into two groups based on the design of their flowers: lacecaps and hortensias, often referred to as "mop heads". The Hydrangea pictured above falls into the hortensia category, with spherical flowerheads of large sterile flowers. Lacecaps are different with their flattened corymbs of flowers surrounded by a single ring of larger-petaled flowers. Lacecaps flowers are difficult to describe, but luckily I found this beautiful example at the Red Hook Senior Center where HSNY planted a garden this year.
Bigleaf hydrangeas come in different shades from pink to purple to blue. These types of hydrangeas are pH sensitive and the blossoms vary based on the level of acidity or alkaline in the soil. More acidic soil makes for bluer blossoms while alkaline soil will make your hydrangeas more pink. A common thought is that all Hydrangea macrophylla are equally sensitive to the pH in the soil, and I can say from experience that there are some cultivars that are less likely to change colors than others. If you are dead-set on having a certain color in your garden, do some research or confirm with your local garden center before buying. Native to Japan and hardy in Zones 6-9, bigleaf hydrangeas should be planted in full sun to part shade and kept well watered. Lastly, to make sure the flowers keep coming back prolifically each year do not cut off the tall stems in fall or winter. Next years flowers bloom on old wood so wait until they leaf-out the following spring and then proceed with selective pruning.
It is hard to find people in the northeast that dislike roses (Rosa spp.), especially this time of year when you come across them in so many colors and fragrances. However, people do love to talk about the dreaded black spot fungus that is so common on roses. Both of these pictures I took in my neighborhood of Astoria, Queens, just last week. Here you can see where roses are their happiest. Roses love full sun, but the other important factor often overlooked is air flow. In both of these cases, the roses were planted without too many other plants crowded around their base. In full sun, in well-drained soil kept moist or slightly dry, with their base kept clean and with adequate air circulation, you can grow successful rose bushes regardless of how green you consider your thumbs to be.

Rudbeckia fulgida var. sullivantii (or possibly the cultivar 'Goldstrum') is commonly called orange coneflower. It is very similar to Rudbeckia hirta, commonly called black-eyed Susan, but the difference is that R. fulgida is more of a true perennial while R. hirta is usually deemed a biennial. Either way this is a North American native wildflower that has become very popular in urban and rural gardens alike. The three-inch flowers are produced above large clumps of upright stems with dark green foliage. Plant Rudbeckia in full sun and keep the soil moist to achieve their full three-foot potential. Do not deadhead to encourage these natives to self sow and spread themselves through your garden. Once established you can divide them every few years to ensure that they stay neat and continue to flower prolifically.
Heliopsis helianthoides is commonly called oxeye.
Oxeye is a plant I was not familiar with until working intensely with North American natives last summer and I was thrilled to find a patch of it near my home here in the city. This upright, sun loving plant grows from 4'-5' and forms clumps of foliage that are more loose in habit than that of Rudbeckia. Native to prairies, meadows, and dry woods, Heliopsis can prove to have some drought tolerance over time. As you can see the flowers are a good size and established clumps produce quite a quantity of blooms for mid- to late-summer. Overall I consider this plant to be carefree and recommend it highly.

All over Queens I find people that grow every kind of sunflower (Helianthus spp.) in their front yards. Even though sunflowers are mostly annuals for our hardiness zone, you cannot help but be presently surprised when you come across one towering over you, especially in this urban setting. I can only imagine how silly I must have looked holding my camera well over my head trying to capture this unbelievable 6'-7' flower. The final result was obviously worth it, though, as this picture continues to make me smile.
Sedum (species and cultivar unknown) is commonly called stonecrop. Most sedum are low growing succulents, members of the Crassulaceae family, and have been acknowledges for their successful role as durable greenroof plants. In addition, there are some upright forms such as the one pictured above that are a nice addition to urban gardens of all shapes and sizes. This plant, possibly the popular cultivar 'Autumn Joy', forms a nice thick clump of succulent foliage that reaches two or three feet. As you might guess being a succulent, Sedum need full sun and prefer well-drained soil, and are quite drought tolerant. The large clusters you see atop the plant in the above picture is actually the plant in bud. Soon these many buds will open to display many tiny, red, star-shaped flowers. The flowers mature from red to a more copper or bronze finish depending on cultivar and continue to be interesting well into the fall. These upright cultivars of Sedum are considered hardy in Zones 3-10.

Friday, July 6, 2007

In Bloom This Week in NYC

(Achillea 'Moonshine' outside of a school building on the Lower East Side)
Yarrow (Achillea millefolium and hybrids) has proven to be an excellent perennial for urban settings. A stiff, well-branched, upright perennial, yarrow grows between 2' and 3' tall and produces striking "flat-topped" blossoms mid-summer. The flowers dry well and can be left on the stalks, which aside from ornamentation promotes the plant to self sow. There are lots of hybrid yarrow on the market so you can find them in a wide array of hot colors. Hardy from zone 3 to zone 9. Flowers best in full sun with moist soil, though I have seen the plant hold up well in dryer conditions.
Coreopsis verticillata and hybrids, or threadleaf tickseed, is a perennial I have come to love so I was thrilled to find this in a community garden on the Lower East Side.
The foliage of threadleaf tickseed is very fine, like that of the annual Cosmos. The flower is yellow however, and depending on the cultivar, can be rich and intense or light and lemony. A North American native of dry woods and open plains, this perennial does best in full sun. Even though it requires supplemental water to get established, Coreopsis can tolerate some drought over time. Deadheading the first flush of flowers can be laborious but for many varieties it will promote a second bloom in fall. This plant is comfortably hardy from zone 4 to zone 8, and grows to a nice mounded 12"-18" tall. I once planted this amidst a hillside of fragrant sumac (Rhus aromatica) in the country and the contrast of texture (the fine Coreopsis with the medium-coarse Rhus) and the burst of yellow color throughout I thought to be a fabulous combination.
Oakleaf hydrangea, or Hydrangea quercifolia, is not typically what most people think of or picture in their mind when they think of hydrangeas.

However, oakleaf hydrangeas are certainly a plant people in the city should know. Cinnamon colored exfoliating bark produces these large pinnately lobed leaves that are easily as big as your hands. Mid- to late-summer flowers are equally large and white in color, maturing pink. Another wonderful characteristic about this hydrangea is that it tolerates shade better than other hydrangeas. This native woody shrub can grow to 6' tall and wide and prefers moist organic soil. Cold hardy from Zone 5 to Zone 9. Not to mention, wait until fall and the red and bronze fall foliage will be sure to impress you.
You can see around town the hostas (Hosta sp. and hybrids) in bloom. Hosta are certainly reliable and durable plants for the New York area, both in the city and the country. Tolerant of deep shade to full sun, these mounding perennials are typically grown more for their foliage which can be large or small, green or blue or variegated, and any combination thereof. Hardy from Zone 3 or 4 to Zone 8 or 9, hostas fill in garden spaces quickly and can easily be divided in fall or spring to go even further. One interesting note that many may not be familiar with is that there are now a number of fragrant hostas available in the trade. Fragrant cultivars often have "sweet" or "honey" or "fragrant" in their names and are available at your local garden center. I used to not be so thrilled about these late summer spikes of flowers, but the fragrant ones I find to be a nice surprise.
Echinacea purpurea, or purple coneflower, is a North American native that loves full sun. With all the talk about bee populations diminishing throughout the city I love to see this plant because it does attract them quite readily. From Central Park to Thompson Square Park I have seen coneflower grown in a number of different settings. When planted in rich organic soil this perennial can grow to 3' or 4' easily and produces a plethora of ornamental purple daisy-like flowers from summer into fall. Coneflower can tolerate dry soils, but this picture taken on the water's edge in Central Park shows that they can be perfectly happy in moist conditions as well.
Here you can see why Cotinus gets it's common name, smoketree. Atop this upright woody shrub or small tree in mid-summer are produced light, airy plumes of flowers, thought to resemble clouds of smoke. Cotinus obovatus, or American smoketree, can grow upright 20' to 30' while Cotinus coggygria, or smokebush, is more of a shrub form reaching 15' tall and wide at full maturity. Either way the straight species of these woody plants has rounded or slightly obovate leaves with an attractive bluish-green color. Newer cultivars have been bred to produce red foliage and flowers and those you may see more readily in the landscape. Plant and prune many of them to add interesting structure to your garden or enjoy one as a specimen. Plant in full sun to part shade, moist to dry soil, Zones 5 to 8.
If you are driving around the country as I was last weekend then you cannot help but see all the common daylillies (Hemerocallis fulva) in bloom in gardens and roadside ditches alike. Hemerocallis has become one of the most extensively bred perennials over the last 50 years and today the color and flower variations are endless and amazing. Hardy from Zone 3 to Zone 10, the only thing you really need to know is that daylillies need full sun and well-drained soil. As the name suggests, the individual flowers only last for a day, but established clumps can get to be quite large and produce many waves of flowers. Once established these modern varieties can be quite drought tolerant. Most daylillies you will find grow to 12" or 18" but some have been bred for height and can surpass three feet or more. While the New York Botanical Garden has the largest display of Hemerocallis cultivars locally, I was presently surprised at the plantings and variation I found walking around Union Square Park.

Monday, April 23, 2007

In Bloom This Week in NYC

First, a reminder. If you haven't yet gotten out to see the magnolias in bloom, treat yourself to a walk, today!
Some times when we focus on ground cover plants for their foliage we forget that they too flower. Pachysandra is certainly a reliable and durable ground cover in New York. The flowers actually have a sweet scent to them, but they are not always so easy to come by. Plant Pachysandra in rich, well-drained soil to get established, and it will do very well for you. Tolerates deep shade. Do keep in mind that Pachysandra terminalis is one aggressive spreader and left unattended it can get a little out of control, especially in the country. For a less aggressive grower, check out the native variety, Pachysandra procumbens.
The cherry trees have definitely popped!
Cherry trees, like pears (below) and crabapples (not quite yet), are members of the rose family (Rosaceae); they have the picturesque five-petaled flower botanists know all too well. You can usually tell the cherries apart with their smooth bark and pronounced horizontal lenticels. As far as their shape, most want to spread out, but there is lots of variation among the different species.
When the pears around the city bloom you can't help but notice. Most likely 'Bradford' Callery pears, these trees are known for their small habit and profuse cloud-like bloom in spring. But don't allow the wool to be pulled over your eyes, these trees are structurally a really bad choice in the landscape. Next time you walk by one, look and see where all the branches fork out, and you will realize that they all emerge from the same spot. Over time added layers of bark end up wedging against each other, eventually promoting this tree to completely split in more ways than one. Not a tree I would quick to plant. Some newer varieties have a better smell to them.
Along the Brooklyn Heights Promenade I found these rhododendrons putting out a fabulous bloom this morning. I would guess by the smaller leaf and flower that they are 'P.J.M. ' hybrids but I couldn't get close enough to ID to species. Here they are in a perfect spot, slightly protected, dappled shade, decent water, and airflow.
Muscari are tiny bulbs in the lily family (Liliaceae). Each bloom is only 4" to 6" tall, but they do have great character for a small flower. Plant in the fall for spring bloom. Well-drained soil, full sun.