Bottlebrush buckeye

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Flowers of bottlebrush buckeye. Judging by the length of the inflorescence, this is probably Aesculus parviflora var. serotina.

I first became aware of Aesculus parviflora, the bottlebrush buckeye, while reading Rick Darke’s gorgeous book The American Woodland Garden (Timber Press, 2002).  Darke shows large, mounding shrubs covered with white wands that look fantastic at the edge of a lawn or among tall tree trunks.  I envisioned an arc of shrubs, eventually growing into a single mass, at the southeastern edge of my garden.  When viewed from the living room windows, they would create a visual frame at the bottom of the lawn, separating it from the vertical trunks of the pine trees beyond.

Well, we’re not there yet.

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Part of the problem is that I seem to have obtained Aesulus parviflora var. serotina which has very long, spectacular inflorescences (up to 60 cm long on my plants) but which tends to grow more upright and doesn’t always have leafy branches down to the ground.  However, the main difficulty is that the place where I wanted them is not the best spot for growing them.  The ground is some of the driest, hardest, poorest soil in the garden, and it seems to be where gravel was dumped during construction of the septic system.  The southeastern edge of the lawn is shaded in the morning but bakes in the sun during the late afternoon, the hottest part of the day.  Grass has pretty much given up, and the “lawn” here consists largely of moss and pine needles.

Despite these difficulties, the A. parviflora that I planted eight years ago now bloom reliably and slowly grow larger.  What I really need to do is edit out some of the tree saplings and brambles that have sprouted among and in front of them.  I’ll dig up the young willow oaks and tulip poplars, but I think the sourwood at the front of the buckeyes can stay.  I hate to destroy such a beautiful and bee-friendly native tree, and once mature, I think its white flowers will complement the buckeyes quite nicely.  I’ll try limbing it up as it grows, until all of its branches are well above the buckeyes.  Then, regular application of a good thick layer of hardwood mulch should help the soil and inhibit sprouting of new saplings.  Maybe in five or ten more years, I’ll have something similar to the pictures in Darke’s book.

Aesculus parviflora is another native-but-not-really plant.  It has a limited range, primarily in Alabama, but is cultivated more widely.  USDA shows it as having a disjunct native range that also includes Pennsylvania and New Jersey, but BONAP’s North American Plant Atlas suggests that the northern records are of naturalized plants.  The flowers attract bees, butterflies, hummingbird clearwing moths (Hemaris thysbe), and the occasional hummingbird, making them ideal for gardeners who care about pollinators and local wildlife.  The plants seem to be generally pest-free, although Japanese beetles do like to munch on the flowers.  Unfortunately, flowering in North Carolina coincides with the peak of beetle season.

Six on Saturday #2

With just under an hour left of Saturday,  here are six pictures from the garden today.  Lots of yellow this week.

1. Alstroemeria ‘Konkajoli’

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Alstroemeria ‘Koncajoli.’

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

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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

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Verbascum chaixii, nettle-leaved mullein

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’

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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’

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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’

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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.

Summer begins

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Male ruby throated hummingbird (Archilochus colubris) at one of our feeders

Last Monday was Memorial Day, the traditional start of the summer holiday season in the U.S.  In my garden, summer begins when the fireflies appear, and the baby hummingbirds fledge.  We spotted the first fireflies a couple of weeks ago, but this week the population increased dramatically.  When the sun goes down, the garden is filled with slowly flashing yellow lights as the little beetles fly up from the grass and flowerbeds.

During the day, the action is a lot more frenetic.  Since early April, a few adult hummingbirds have been visiting our two feeders, which I refilled once a week or so.  But suddenly there are dozens of hummers jockeying for position, and we go through a liter of sugar solution a day.  Their harsh chattering and the sound of buzzing wings fills the air as they dogfight over the lawn and chase each other away from the feeder or favorite flowers.  Occasionally several will settle down to drink peacefully at the same feeder (four on the small, six on the large), but it never lasts long.  Another soon shows up and starts a chain reaction fight in which the tiny birds orbit the feeder like fighter ships in a Star Wars movie.   I have counted ten or more at a single feeder, and the other is just as busy.

Ruby throated hummingbirds

On dry, sunny roadside banks and meadows, patches of bright orange show that the blooming season of native butterfly weed (Asclepias tuberosa) has started, and as Spigelia marilandica finishes flowering, A. tuberosa takes over as my favorite flower in the garden.

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Asclepias tuberosa. The best specimen in the garden is a volunteer seedling that sprouted in the gravel path beside the mint patch.

This is one of the best insect plants that you can grow in North Carolina.  Like all milkweeds, it is a food plant for the caterpillars of the monarch butterfly (Danaus plexippus).  Monarchs are becoming very scarce, sadly, and in ten years gardening at this location, we have only had caterpillars one year.  But A. tuberosa flowers provide food for bees and other butterfly species, and those are not in short supply:

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Carpenter bee (Xylocopa sp.) visiting A. tuberosa flowers
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Pipevine swallowtail butterflies (Battus philenor) on A. tuberosa

When the plants are finished flowering, they attract beautifully colored milkweed bugs (Oncopeltus fasciatus) that feed on the developing seeds.  But no matter; enough seed survives to float away on tufts of fluff, so that more plants appear every year.

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Oncopeltus fasciatus nymphs on A. tuberosa follicles.

Once planted, A. tuberosa can be tricky to transplant, because its tuberous roots grow deep and break easily.  If you plant a couple of potted seedlings, they’ll cross-pollinate and give you plenty of seed that you can spread around.  It seems to take about two years for seedlings to reach blooming size, and a couple more to grow a really nice clump.

Much less colorful but still elegantly beautiful, Yucca filamentosa is also blooming now.  I planted it on the dry mound around our wellhead, along with the prickly pears and a few other xerophytic plants.

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Yucca filamentosa

It was supposed to be the variegated clone, ‘Color Guard,’ but it seems to be some sort of unstable mutant.  New growths come out variegated, but over the course of the year, they darken until they are indistinguishable from a wild type plant.

On the other side of the house, Hydrangea quercifolia, oakleaf hydrangea is also blooming white.

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Hydrangea quercifolia

This is a southern species, with a native range centered on Alabama.  It is a much more reliable bloomer than the Japanese Hydrangea macrophylla, because the new growth is less susceptible to damage by late freezes.

Some cultivated clones have inflorescences made up entirely of large sterile flowers, equivalent to mophead forms of the more familiar H. macrophylla.  However, I prefer the look of wild type plants, equivalent to a lacecap H. macrophylla, with a few sterile flowers surrounding clusters of tiny fertile flowers that attract many bees.

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The H. quercifolia flowers are looking their best this week, and they’ll continue to look good until the Japanese beetles, the scourge of summer, arrive to devour them.  That could happen any day.  I saw a few beetles this week, munching on banana leaves, but most will emerge over the next couple of weeks.  If I can keep the beetles from doing too much damage to the hydrangea, its inflorescences will slowly turn pink and will be attractive until well into autumn.  Eventually they’ll dry out and turn brown, but they’ll remain on the plant and, together with the peeling bark, provide winter interest.