Natives in Pots

There are many reasons to grow outdoor plants in containers. You may not have space in the ground, or they can be used as decorations on a deck or patio, or you may just want to bring the plants closer to where the people are. The main reason I have been growing native plants in pots is that I do not have the right growing conditions in the ground to raise the the plants I want from seed. This is particularly the case for annuals from some of the hotter parts of the country.

Here are some of the plants that I am growing this year. Lantana, Lantana camara, is technically a North American native, since its native range includes Mexico and Puerto Rico. It behaves well as a bedding or potted plant in colder climates, but it is invasive in the warmer parts of the US, particularly Florida and Texas. I really love the red-orange-yellow multi-colored flowers and long blooming period.  These I bought from a nursery and mixed in with other classic annuals like the Lobelia, shown here.  The rest of the annuals I have grown from seed.

While on a trip to Austin, TX, I picked up seeds for Drummond phlox, Phlox drummondii, and the annual Indian Blanket, Gaillardia pulchella, at the Lady Bird Johnson Wildflower Center. These appeared to be species plants and not any crazy cultivars. So far the Phlox has made it to bloom, with its scarlet red flower. The Indian blanket is just a week or so away. Another Texas native I have growing in pots and in the ground is Scarlet Sage, Salvia coccinea. None of these plants really started growing until the temps here got well into the 80’s.

I was really happy to see that some seed from the Beach Sunflower, Helianthus debilis ‘Pan’, that I grew last year had germinated in the same pot. Native to the Texas coast, this species has spread up the East Coast all the way to Maine. Here it is in bloom last year in the same pot. I have also grown Bearded Beggarticks (Bidens aristosa) in pots. Given half a chance, this eastern native reseeds itself readily.

Some native annuals that I had in pots last year are Devil’s Claw (Proboscidea louisianica), Yellowdicks (Helenium amarum ‘Dakota Gold’), and Bird’s Eye Gilia (Gilia tricolor).

The native perennial that I have in a pot is the Crimson-eyed Rosemallow, Hibiscus moscheutos, that I bought from the New England Wildflower Society. While it is native to New England, I just don’t have the sunny moist site it would like to keep it in. I over-wintered this in its pot by storing in a plastic bag with salt marsh hay in an unheated garage. It looks pretty happy so far. The blooms are expected in late summer.

Rock Harlequin, a Native Corydalis

I first ran across Rock Harlequin, Corydalis sempervirens, while climbing around a rocky slope when I noticed the pink and yellow flowers poking up out of a crack in the rocks. It seemed so odd that such delicate flowers would be in such a seemingly harsh habitat. In fact these plants do very well in harsh conditions like exposed stone walls and shallow, dry soil conditions, but it does not like too much heat. Other common names for this plant are Pale Corydalis and Tall Corydalis. I like the Rock Harlequin name, since for me it pop out of the rocks like some kind of joker.

Its native range is all across Canada and south from Minnesota over to Georgia (in the higher elevations). C. sempervirens is found in throughout Massachusetts, excepting Barnstable County and the Islands. Its native habitat is in dry or rocky woods and often on sites after a disturbance.

It seems as if it can deal with poor soil better than it can handle competition with other plants on a richer site. This was borne out in my garden when I put a few plants on the edge of a mass of Yellow Corydalis , C. leutea, in cool moist soil. The Yellow Corydalis completely engulfed the Rock Harlequin within 2 weeks, never again to be seen. I had much better luck on a dry site on the edge of the driveway where not much else would grow.

Corydalis sempervirens is not so much an annual as it is a biennial or short lived perennial, producing a large amount of seed and moving around the garden. Like an annual it will flower in its first year from seed. The highly dissected gray-green leaves occur all along the upright, branched stem. The ¾ inch long pink and yellow tubular flowers are borne in panicles at the ends of the foot-long branches. Blooming time begins as early as May, for year old plants, and continues sporadically though September.

Fresh seed, or seed kept cool and moist, are best for starting this plant. Seed started indoors should be moist stratified for 60 days and then be planted shallowly as light is needed for germination. Seeds are available from a few sources, including Summer Hill Seeds. I have started two batches of seeds with excellent results, high rates of germination and strong seedlings.

This year I started seed, before I figured out if I had a place to put the new plants, since space around the garden is filling up. Then I remembered where I first saw the plants, so I put a little soil in the cracks in a garden wall (over a layer of landscape fabric) and stuffed in a few plants. After a few days they seem to be adapting to their new home. With any luck they should be blooming in a couple of weeks.

For more information on this plant check out this link to the Wildflower Center's Database.

Dealing with Cultivars and Clones, something to consider for Wildlife Gardeners: A Garden GOOPS

It’s not exactly the first of the month, but it is my first posting written in June, so Joene asked me to share some of my garden GOOPS (see Joene's Garden Oops). Just in the past week the following situation came to light and I would say it qualifies as a GOOP.

A few years ago I bought 2 Viburnum nudum ‘Winterthur’ for the attractive summer and fall foliage and the promise of multicolored berries turning into treats for the birds. So far I have not seen more than 1 or 2 sad little berries. What I learned recently (pointed out by Ellen at Turkey Hill Brook Farm) was that many Viburnums, including V. nudum are self-sterile. This means to get viable fruit it needs a pollen source that is genetically dissimilar but from the same (or compatible) species. So in my case a different cultivar of V. nudum, or the straight species will be in order. As luck would have it, I found a species form just the other day, so I snapped it up. Now I just have to find a nearby place for it.

This situation is better known when dealing with blueberries, where at least 2 genetically distinct cultivars, with similar bloom times, are planted in proximity in order to get a good yield of fruit. Since many blueberries are labeled as early-, mid- or late-season blooming selections, it is easier to match up the right plants.

For the garden planner, a similar situation occurs with plants that are dioecious, that is, having male and female flowers on separate plants. This is well known with hollies. Since the red berries on the female plants of many hollies are an important attribute, male counterparts for each of the female cultivars have been identified with similar bloom times.

Most cultivars are reproduced by some asexual means, be it cuttings, grafts, divisions or tissue culture. This ensures that every plant you get performs the same, since they are all genetically equivalent. What you get with a such a cultivar is consistency and reliability of performance. This includes size and shape, bloom time and color, as well as disease resistance. For edible plants, like apples and blueberries, you could include properties of the produce, like size and taste. From a design point of view cultivars can make a more effective composition where consistent size and color are important factors. Also the reduced fertility of some cultivars means you don’t have to deal with ‘nuisance’ seedlings and squishy fruits. 

Even plants that are not labeled as cultivars may have been reproduced asexually.  It is much faster to grow a mature plant by cuttings and divisions, than it is from seed, but there are consequences.  What you lose with these genetically identical plants is diversity. Over a series of generations, if the plants can reproduce, you decrease the gene pool and the ability of the population to adapt to change.

In working with plants that are introductions, not native to an area, this reduced fertility can be seen as a way of reducing the invasive potential of this new plant in the environment. For example, for many years the Bradford pear was a sterile clone. Even overused as it was, it did not spread by natural means. Recent cultivars, with improved branch strength over earlier forms, have inadvertently developed increased fertility which may set the stage for an invasion.

For the gardener who wants to maximize the diversity and wildlife value of their gardens by producing fruits and viable seeds, knowing which plants are dioicous (separate male and female plants) and which are self-sterile will be an important guide in the selection of plant materials. For those lucky enough to be living near wild populations, or having neighbors with similar, but genetically distinct, plantings there may be diversity enough. However for the isolated wildlife gardener, surrounded by a suburban monoculture of lawns and Bradford pears, you may be on your own in creating your own ark of diversity. I am always one the lookout for seed-grown plants and open-pollinated seeds as a means of broadening your local gene pool.

If you like like to read more on Viburnum pollination, check out the discussion at Dave's Garden.

The Natives are Restless - What's happening as Summer approaches

As spring is drawing to a close, many of the summer blooming natives are getting ready to pop. This week I wanted to give an update on how the Native plants in my garden are doing.

I was very pleased to see that the Alleghany Vine, Adlumia fungosa, has begun to bloom with its little pale pink hearts. Last year it did not begin to bloom until mid-late June. This year I am letting it find its way in a more natural way, rather than forcing it to climb a trellis. In this way it is less likely to be twisted and broken off in the wind. IOt is a little difficult to see with its delicate frilly foliage and light colored flowers.  Now I just have to avoid stepping on it.

If these plants do well I will add in some new ones that I started from seed this year.  I hope that will get a stable population growing.

The little Rosy Sedge that I talked about a few weeks back is getting closer to bloom. This particular plant is so heavily shaded that the inflorescence, in fact, the whole plant is about half the size it gets in a more open location. I would never have spotted this development if I were not actively watching for it. I hope I can show you a good image when its flowers are actually open.

Correction: Two Stems of Meadowsweet

I have two native Spiraea growing here, Steeplebush and Meadowsweet, S. tomentosa and latifolia (or alba), respectively. While there can be easily distinguished by the different shapes of the flower spike, the leaves are also different. This is the first year that I could clearly detect the difference in the leaves. Steeplebush has a soft fuzzy leaf relative to the smooth leaf (glaborous) of Meadowsweet. In the photo you can also see that leaves of the Meadowsweet and more relaxed, but that is hard to tell if you don’t have a side-by-side comparison. While the habit of these two spiraeas is rather open, relative to the tightly mounded Japanese Spirea (S. japonica), I am surprised that these native species are not used more often in the residential landscape. In my garden Meadowsweet has proven to be a very versatile shrub, growing under a wide variety of conditions and blooming throughout the summer. It also can be pruned to tame it exuberant growth without compromising its ability to bloom.

The Red Columbine, Aquilegia canadensis, is still blooming away. Here it is shown with one of my Meadowsweet bushes just behind it.










Lastly, I planted two Winterthur Viburnums (V. nudum ‘Winterthur’) 4 years ago and they are both hitting stride now. (Their slow development was due at least in part to their proximity to the shade of a Norway Maple.) These buds will open to form corymbs of small white flowers. More interesting will be the pink and blue berries to follow.

American Bellflower

All around my yard I have mini-invasions of the attractive-yet-aggressive perennial Creeping Bellflower, Campanula rapunculoides, with is tall raceme thick with 1” purple bells. This European import is prevalent in disturbed areas, but according to Forest Service, it is not believed to be a threat to undisturbed natural habitats. When I learned about a native bellflower that also produced tall flower spike I got excited and got hold of some seed. American Bellflower, Campanulastrum americanum, is a biennial, spends its first year as a rosette of foliage and then launches its flower spike, up to 5 feet, in the second year. Despite the similarity in the name, the American (or Tall) Bellflower is a very different plant from its creeping cousin. Its flowers are like sky blue stars rather than bells and very tall flower spike is rather leafy and not as densely populated by blooms. Also, American Bellflower reproduces by seed only and does not form underground runners.

The native range for Campanulastrum americanum is from Ontario to Minnesota and south to Florida. As such, there are not any native populations in Massachusetts. Its native habitat is in moist borders and open woods. While it may grow in full sun, it prefers cool conditions.

I put in seedlings in all parts of my yard ranging from dry shade to full sun in well drained soil, to see just how they do. These plants survived in all locations. In areas with fertile soil and lots of sun, the flower spike reached nearly 6 feet. In the dry shade it topped out at about 2 feet and did not bloom as intensely. It even survived under a Norway Maple. It does reseed itself quite well, where the seed can find good soil. I have way too many seedlings this year, but they are not so prevalent as I get with the Swamp Marigold, Bidens aristosa, growing in the same area.  By recognizing the rosette with its 1/2-1" heart-shaped leaves, you can mange the population by transplanting or removing excess plants.

The flowering period is from July to October. The first flush is strong then blooming continues slowly throughout the summer. While not as full as the first flush, these plants will produce fresh blooms later in the fall. I tried cutting some flower stalks back to generate new spikes at mid-season, but this was not too effective. Maybe this year I’ll try that earlier. Seed that is produced early in the season may ripen quickly and germinate to produce a rosette that year, essentially functioning as a winter annual.

Also of interest, C. americanum is on a list for plants suitable for use under walnut trees, having both resistance to the juglone and a tolerance for shade. Hummingbirds are reported to visit this plant and it has been used to treat coughs and respiratory ailments by the Iroquois and Meskwaki Indians.

Seed for C. americanum is becoming more available. I was able to get seed from both Prairie Moon Nursery and the New England Wildflower Society (NEWFS). In discussing native plants with Scott LaFleur of NEWFS, he felt that despite its vigorous nature in size and reseeding, this plant could do really well in the garden. From my experience I see that it may find its garden home in the back of a shady border or in a cottage garden, where it leafiness will blend in with the other masses of plants.  Since this plant is not native to the New England States, I would not recommend its use up here in areas near to natural areas where its seed may escape.

American Pennyroyal - Another Native Groundcover

While it may be a little late in the season to talk about starting annuals from seed, but I thought American Pennyroyal was worth mentioning here. It is a tough little plant that grows in dry, partly shady locations and is quick and easy to germinate.  It has a low-growing (6-12”) and spreading habit qualifies it as a native groundcover.

American Pennyroyal, Hedeoma pulegioides, is a low growing herb of the mint family that has been used extensively by both Native Americans and the colonists for its medicinal properties. Medicinal uses include treatment for colds and fevers, as a gastrointestinal aid (‘warming to the stomach’), and as flavoring agent in foods, like tea and ice cream. The colonists readily accepted this herb as a replacement for the European or English pennyroyal (Mentha pulegium) that they were accustomed to using. The plant is rich in a pungent, volatile oils including pulegone (whence the species name), which holds most of the medicinal properties; however, large doses are reportedly lethal. For the hikers, rubbing the leaves on your skin repels mosquitos and other biting insects.

The plant grows in dry upland woods and can occur as rather dense colonies. In nature, it is often found growing in openings in the woods and along paths. The native range runs all along the East Coast (except Florida) and west to Oklahoma and North Dakota.
Small blue tubular flowers are borne in the leaf axils of the erect stems from July to September. While the flowers do attract some tiny insects, they are difficult to see unless you get down on your hands and knees.

The real garden value of this plant is in its aromatic character and its ability to grow thickly in dry partly shady conditions. I am putting it along walkways so that you get a burst of the minty aroma anytime it is disturbed, or stepped on. I started my first ‘crop’ in 2009, with seed from Companion Plants, and am seeing new colonies springing up in adjacent areas. It is easy to distinguish from other sprouts, because as soon as you touch it you get a whiff of its minty aroma. This is a good example of what I am looking for in a native annual, that is, an annual plant that is able to persist on its own without my direct involvement and has desirable garden traits. In the case of American Pennyroyal those are its stimulating aroma and ability to grow in dry partly shady locations. 

Native Ground Covers - Part 2

In the last post I listed some of the herbaceous and small woody native plants that I have been using as ground covers. Sometimes you want that grassy look. There are a number of options for low maintenance grasses as alternatives to the Non-Native Kentucky Blue Grass and Perennial Ryes commonly used in residential lawn grasses.

One option to the conventional lawn is the use of fine fescue grasses.  These have a silkier appearance and tend to be a lighter shade of green than KBG.  Two commercially available seed mixes based on blends of fine fescue grasses are ‘No-Mow’ Mix from Prairie Nursery and Eco-Lawn from Wildflower Farm. These mixes contain a blend of creeping and clumping fescues, some of which are native to North America, which will tolerate a range moisture and light of conditions. Lawns of these grasses are reported to require very little mowing (1-4 times/year), little additional water and no fertilization.

Another option is to do a sedge lawn. Sedges, members of the genus Carex, number about 2000 species world-wide, with about 480 representatives native to North America. With so many species, there are some that are adapted to nearly any growing condition. In general, they look like average grasses. This genus can be distinguished in that sedges have triangular, not round, stems. When viewed down the stem the leaf blades radiate off at 120-degree angles. Sedge lawns are a better choice for wet conditions than fescues, however they do not tolerate foot traffic as well. Brooklyn Botanical Garden has a useful article on sedge lawns.

The first sedge that I became intrigued with was Rosy Sedge, Carex rosea. I saw this ‘in bloom’ in a friend's yard with its tiny (~1/8th inch) rose or star-like, tan colored inflorescences. These come in late spring. Otherwise, it just looks like grass. Unfortunately, I do not have a photo or these little flowers at this time, but here’s what it looks like without them. While it is naturally distributed over the eastern 2/3rds of the U.S., I do not know of a commercial source for this sedge.


Since first seeing Rosy Sedge, in 2006, I have become more interested in these plants. Two sedges that are available and well adapted for use in the Northeast are Pennsylvania Sedge (Carex pensylvanica) and Appalachian Sedge (C. appalachica).

Appalachian Sedge forms clumps with mid-green blades 8-24” long. These clumps do not produce rhizomes. The bloom time is in late spring, with seeds forming in late spring to early summer. Its native habitat is in dry to mesic deciduous forests and its native range includes the eastern states from Georgia to Canada. In my yard I have it growing successfully under a Sycamore Maple (another invasive tree). The foliage turns tan over the winter, but it greens up rapidly in the spring.

Pennsylvania Sedge is becoming much more available in the nursery trade. It is a little smaller than Appalachian sedge, with leaves at 4-18 inches. It is reported to tolerate occasional mowing (I haven’t mowed mine yet on purpose, anyway). Also it does spread slowly by rhizomes, a good trait for a lawn grass. The inflorescences appear in early spring as dark brown spikes, just above the foliage. These come before and are easily distinguished from the flowers of Appalachian Sedge. This sedge is found in well drained acidic, but rich soils in and along hardwood forest edges and openings. The native range includes the eastern states from Georgia to Canada to just west of the Mississippi River. My Pennsylvania Sedge is also doing well under the same maple tree. Mine is a bit larger than the Appalachian Sedge, but it has been in the ground a year or two longer. For me the beauty of both of these grasses is that they do well in DRY SHADE!!!

For more general information on growing alterative lawns check out the following links:
>Planting a ‘No-Mow’ lawn. This link also has a clear and concise statement on growing/encouraging moss.
>Native Grass Lawns: Lots of information on a variety of altenatives
>Planting a Native Grass Lawn. This is another useful link for the Brooklyn Botanical Garden site.
The book, Easy Lawns, edited by Stevie Daniels, gives information on growing low-maintenance native grass lawns appropriate to each region of the U.S.