Recently, I was walking along Morgan Creek in Chapel Hill, not far from the North Carolina Botanical Garden, when I noticed what I took to be an unusually extensive and dense population of Hexastylis arifolia, the little brown jug.
Closer inspection revealed that the plants were actually Cyclamen hederifolium, a native of Mediterranean Europe. The plants were growing on a steep hillside, where rocks and loose soil have slowly slid down the slope. A few plants extended onto the wetter, more compacted soil of the flood plain, but that was clearly not their favored habitat.
Nearby were a few plants of the real Hexastylis arifolia.
These Cyclamen hederifolium plants had clearly escaped from cultivation, but I don’t think they can really be considered invasive. The true invasives are plants that form dense stands, choking out native species–things like Eleagnus species, Ligustrum sinense (Chinese privet), Hedera helix (English Ivy), Pueraria montana (Kudzu), and Microstegium vimineum (Japanese stiltgrass).
Cyclamen seeds are distributed by ants, so the plants are unlikely to spread as far as those species with windborne seeds or berries that are eaten by birds. The relatively sparse and low-growing leaves of C. hederifolium are also unlikely to smother other woodland plants–not that there is much else that likes to grow in the dry, unstable soil that the cyclamens seem to favor.
Not far from the cyclamens, I did see several other species with more potential to be invasive. Mahonia bealei (leatherleaf mahonia) and Ilex cornuta (Chinese holly) were naturalized in the woods, and of course, English ivy is ubiquitous. The beautiful variegated leaves of Arum italicum stood out in the wet soil near the creek. I had been thinking of adding A. italicum to my garden, but given its ability to spread and potential to be invasive in the mid-Atlantic region, I’m now not sure that’s a good idea.
Although the C. hederifolium are probably no threat to native ecosystems, seeing them in an ostensibly wild area was a good reminder that the plants we grow in our gardens may not always stay there.
Another Saturday, another six things in the garden. Thanks to The Propagator for suggesting this idea and for hosting links to other ‘Six on Saturday’ participants.
1. Lilium catesbaei (pine lily)
Lilium catesbaei grows on the coastal plain from southern Virginia to eastern Louisiana. It is a plant of open, fire-dependent pine savannas, where it often grows among carnivorous plants, orchids, and other plants that favor damp, acidic conditions. L. catesbaei is rarely available from nurseries, but about fifteen years ago, I grew a batch from seed obtained from another member of the local orchid society. In recent years, the number of blooming plants has decreased until this year there are only two flowering. I think it may be time to dump out the pots, assess what I have left, and repot in fresh soil.
2. Lantana camara ‘Miss Huff’ (Hardy Lantana)
Lantana ‘Miss Huff’ seems to be the hardiest commercially available clone of L. camara, and it is the only one that has successfully over-wintered in my garden. I have three plants in sunny, moderately dry spots. They freeze to the ground each winter and new growth emerges several weeks after the last frost. By late summer, the bushes are about 6′ (~2 m) tall and wide. Usually, I see the first flowers at the end of May, and then the plant blooms non-stop until the first frost. Buds and young flowers are bright yellow-orange, maturing to a darker orange and then fading to pink before dropping.
The flowers are moderately attractive to hummingbirds and attract large numbers of butterflies. It’s a great plant for guaranteed color even in the hottest and driest summers.
3. Vernonia glauca (Broadlead Ironweed)
Vernonia glauca is a true piedmont native, found primarily in Virginia and North Carolina. I obtained seed about ten years ago from the North Carolina Botanical Garden seed distribution program. I initially grew them at the back of a flower bed with other tall perennials, but the seeds, each with a tuft of fluff, have been carried on the wind all over the garden. At this point, it is almost a weed, and the long taproot makes it very difficult to eliminate. Beware seeds that have their own parachute.
4. Titanotrichum oldhamii
I currently have two semi-hardy gesneriads blooming in the garden. The first, Titanotrichum oldhamii, is native to China (Fujian Province), Taiwan, and Japan. I love the bright yellow flowers that resemble foxgloves. I bought my T. oldhamii plant last year, so it has survived one winter in the garden so far, and has come back bigger and stronger this year. It is growing in the shade of a large Callicarpa americana (American beautyberry) in fairly rich, well drained soil.
5. Seemannia nematanthodes ‘Evita’
The second gesneriad is a native of Argentina. Seemannia nematanthodes ‘Evita’ seems to grow equally well in the ground or in pots and hanging baskets. I started with a couple of stems in a 3″ diameter pot, but the plant expands exponentially each year. In autumn, the above-ground stems, thin underground rhizomes, and roots die back, leaving small, scaly rhizome segments that look disturbingly like maggots. These rhizomes can be left in the soil or stored dry in a plastic bag.
In addition to growing Seemannia ‘Evita’ in semi-shaded beds around the garden, I keep a couple of potted plants. When it is time to repot in early spring, I usually have far too many rhizomes, so I add the extras to the flower beds. Consequently, I don’t really know how hardy Seemannia ‘Evita’ is, because I can’t be sure which of the plants blooming now are derived from rhizomes that survived the winter in the ground, and which are from rhizomes planted this spring.
6. ‘Celeste’ figs
These figs from the garden were dessert yesterday. I grow three varieties of Ficus carica: Celeste, Black Mission, and Conadria. Of the three, Celeste is the hardiest and most productive, so it isn’t surprising that it is the most commonly grown variety in this part of North Carolina. Celeste figs are small but intensely sweet, and if I don’t pay close attention they’re eaten by birds, squirrels, wasps and ants as soon as they are ripe.
That’s my six for this week. Now, I have to go outside and attempt to dislodge a squirrel that is building its nest under the solar panels. Hope I don’t fall off the roof.
With just under an hour left of Saturday, here are six pictures from the garden today. Lots of yellow this week.
1. Alstroemeria ‘Konkajoli’
I have tended to avoid Alstroemeria hybrids, because many are reported to be invasive. This was advertised as a civilized cultivar that doesn’t take over the flowerbed. After two years, I’m starting to wonder if it is too civilized. It seems to produce just one stem at a time and shows no inclination to form a nice clump. Pretty flowers, though.
2. Hydrangea quercifolia
When I blogged about oakleaf hydrangea a couple of weeks ago, I mentioned that the flowers would soon fade to pink. Well, they have.
3. Verbascum chaixii
Unlike many mulleins, V. chaixii is a perennial rather than a short-lived biennial. I have both the yellow- and white-flowered forms growing in the sunnier areas of the garden. Hoping for volunteer seedlings but haven’t seen any yet.
4. Ligularia japonica ‘Chinese Dragon’
This species isn’t thrilled with our hot summer, but it seems to do reasonably well in the shade of a dogwood tree. The deeply cut leaves and big yellow flowers are interesting, but I really like the flower buds. They are ribbed longitudinally and look like miniature green pumpkins.
5. Canna ‘Tenerife’
Canna season has started, which means lots of bright flowers, lush foliage, and constant checking to make sure that caterpillars of the lesser canna leafroller moth (Geshna cannalis) aren’t feasting on leaves that they seal with a loop of silk before the young foliage can unroll. The leafrollers are ugly, maggoty-looking things that skeletonize canna leaves and make a mess with their frass. I hate to use pesticides on plants that attract so many pollinators, so I have to squish the caterpillars by hand. Yuck.
6. Canna ‘Pacific Beauty’
The flowers of this clone look almost fluorescent against the dark brown/purple foliage. In this climate, cannas can be left in the ground year round, as long as the rhizome is planted six or eight inches deep and mulched well in the autumn.
The books all say that Cyclamen hederifolium (ivy-leafed cyclamen) blooms late summer into autumn, but most of my plants started flowering just before the solstice. At this time of year, there’s so much else going on in the garden that it’s easy to overlook these little pink flowers in the darkest spots under the deciduous canopy.
People who don’t grow orchids often consider them to be difficult. People who do grow orchids sometimes feel the same way about terrestrial orchids, particularly hardy species. Your average orchid grower is perfectly happy messing around with ultrasonic humidifiers, high tech fertilizers, and complex potting mixes containing exotic and expensive materials, both organic and inorganic, in an attempt to grow a delicate little epiphyte from Borneo or the Peruvian cloud forest. But give them an orchid that grows in the ground outside, and they are at a loss.
Bletilla striata, the Chinese ground orchid, is one species that defies the expectations of both orchid growers and those who just admire orchids from afar. It’s a terrestrial orchid that is very easy to grow, and given a modicum of care it will steadily increase in size until you have a huge clump to impress your friends. If you can grow a daffodil, you can probably grow Bletilla.
According to IOSPE, Bletilla striata is native to China, Korea, and Japan (people in the latter nation might have something to say about calling it the Chinese ground orchid). I’m not sure where in its fairly wide native range the plants in cultivation originate, but they are certainly cold hardy. My plant has easily survived 5 F (-15 C), and the species is reported to be hardy in USDA Zone 5 (-10 to -20 F, -23 to -29 C winter minimum) with protection. My plant is growing in my standard mix of native clay and permatill, top-dressed with hardwood mulch, but any reasonably well-drained, slightly acidic garden soil would probably be fine. Morning sun and some afternoon shade will provide sufficient light for flowering without scorching the leaves.
The flowers are relatively short-lived and don’t have the greatest form, but the buds open successively for several weeks. In addition to the standard pink form, there are alba (white-flowered) and coerulea (“blue”) forms. Several clones with variegated leaves are also widely distributed. This spring, I obtained several pseudobulbs of an alba clone at a very reasonable price from one of the big bulb vendors. I’ll be interested to see if it grows as easily as the typical form.
If Bletilla striata has a flaw, it is its eagerness to grow in early spring, at least in our mild climate. The pseudobulbs are fairly close to the soil surface, so they warm up quickly and often initiate new growth in February, long before the last freezing weather. Although dormant plants are very cold hardy, the new leaves, and especially the flower buds which emerge simultaneously with the leaves, are very sensitive to frost. Leaves will continue growing even if the tips freeze, but frozen buds mean no flowers until next year.
This past winter, we had very warm weather in February, and new growth was well under way when a low of 25 F (-4 C) was forecast. In an effort to save inflorescences that were already starting to emerge, I covered the entire clump with a black plastic cement mixing tub and several inches of mulch. I keep several of these sturdy tubs around to serve as water reservoirs for potted bog plants, and they are also very useful for covering tender plants. After several days, I removed the tub so that the new growth wouldn’t rot in the humid darkness and then replaced it again when more freezing weather was forecast. The procedure was labor intensive but worked perfectly, and this year’s display of flowers is probably the best yet.
In my post about Calanthe sieboldii, I mentioned that the hybrid Calanthe Takane was in bud. The flowers are now open, and I am quite pleased. C. Takane is a cross of C. sieboldii and the much smaller and less colorful, but hardier, C. discolor. My C. Takane shows its parentage in the yellow lip (from C. sieboldii) and reddish brown sepals and petals (from C. discolor). It is intermediate in size between its two parents. Take a look: