Thursday, August 19, 2021

Savoring Sumac

Hydrangeas are in, yews are out.  Interest in vegetable gardening swings with the tides of economics and pandemics.  In the hippest neighborhoods, spider plants in macrame hangers have even made a comeback.  Public opinion on native plants is on the way up, too.  In my collegiate plant identification classes, our professor would say “it’s just a native,” somewhat disparagingly, when we looked at an eastern red cedar or tuliptree.  Today, those on the front of one of the trendiest gardening curves are going native and banning non-indigenous plants entirely, or are trying to plant gardens which are composed largely of native plants.

Some natives, such as bottlebrush buckeye and the sugar maple, are attractive and easy to invite into your personal landscape.  Others, like poison ivy, would only be employed in the garden of a sadist.  I’m interested in the plants which people deem in-betweeners, such as sumac.  In England years ago, I was approached by a nicely dressed gentleman, who guessed I was an American.  “Our favorite plant comes from your country,” he said.  I guessed it must be the giant redwood, a certain hybrid tea rose, or perhaps a rare orchid.  “No,” he replied, “it is sumac.  It has the most magnificent fall color and beautiful fruit!”  Our new love of natives hasn’t discovered sumac yet, so I’m here to promote its case. 

Locally, sumac species such as staghorn (Rhus typhina) and smooth (Rhus glabra) grow wild in hedgerows, right-of-ways, and abandoned fields.  This “wildness” may be part of the discord, since sumac defies pruning into meatballs or hockey pucks and will always look shaggy and primordial.  Sumac supporters point to cultivars with dissected, lacey foliage that is prettier than the common types, such as Rhus typhina ‘Dissecta’ or ‘Laciniata,’ both with finely cut leaves.  I’ve had ‘Laciniata’ in my garden for decades, and found it not wildly rampant from seed or sprouts.  While it has moved fifteen feet from its planting spot, seeking more sun, the very few unwanted runners have been easy to remove.    

“But it is poisonous!” the sumac-phobes will proclaim.  Nonsense.  These sumacs are fine to touch.  In fact, poison sumac (Toxicodendron vernix) grows primarily in bogs, has white (not red) berries, is closely related to poison ivy, and is not common locally.  Once again, the name is the problem, not the plant.  Perhaps sumac needs a new image and a re-boot, a process which succeeds with some politicians and certain consumer brands.      

Sumac is useful, too.  Legendary Master Gardener Winnie Lustenader, an edible wild plant aficionado, offered up a truly delicious lemonade made from sumac berries.  Sumac fruits also make excellent fuel for a beekeeper’s smoker, the device used to calm honeybees while the prodding around in their hive.

In closing, I must quote the famous plantsman Michael Dirr, who opined in his Manual Of Woody Landscape Plants, “Europeans have long appreciated Rhus glabra and Rhus typhina.  Perhaps, someday, Americans will become more introspective and appreciative of our rich woody plant heritage.” 

Monday, August 2, 2021

A Brush With Greatness

Sometimes the worst garden disasters create happy endings.  This was the case for our Norway spruce.  A towering giant, it was hit by lightning in July 2015, giving it a fatal trunk crack from top to bottom.  While I was glad the tree took the jolt rather than the house, its removal left an ugly blank patch which quickly started to fill with weeds.  Faster than an American Pickers guest star at a tag sale, I started acquiring and installing new plants, including two winterberry hollies, a spicebush, a moosewood maple, and best of all, a bottlebrush buckeye.

If you look in your woods for bottlebrush buckeye (Aesculus pavia) and don’t find it, please forgive me.  I admit that calling it native is a bit of stretch, since the most extensive natural populations are found in central Alabama, with nary a sprig in New York.  But get to know this outstanding woody ornamental, and you’ll be hooked, too.  The Morton Arboretum calls it a handsome shrub with memorable flowers, while British botanist William Jackson Bean wrote “no better plant could be recommended as a lawn shrub” and Wayside Gardens proclaims it “one of the best flowering shrubs for the summer.”  While I freely admit that Wayside doesn’t go in for understatement regarding anything they sell, for an Englishman to give high praise to an American plant, it has to be good.

So, let me tell you why bottlebrush buckeye is a plant of special merit.  First, it has great foliage and form.  Its medium green leaves are palmately compound, giving it a unique texture, and it develops into a dense mound ten to twelve feet high and at least as wide.  Unless you want to block the view out your first-floor windows, don’t plant one near your house.  Instead, locate it on the margin between lawn and woodland, where it excels.  Bottlebrush might also be grown as a small tree, but the plant’s spreading nature would then require management, which seems a shame.  Better to plant it someplace where you can let it branch to the ground and spread a bit.  As garden writer Margaret Roach keystroked, “Give it plenty of room–and I mean plenty–and it will make a beloved companion for decades to come.” 

Plantsman Michael Dirr wrote “there are few summer flowering plants which can rival this species.”  The delicate white flowers are borne in cylindrical panicles up to 18 inches tall, dozens of which will appear on a mature plant in late July.  Although the name “bottlebrush” sounds a bit prosaic, it aptly describes the form of this floral display.  The buckeye fruits, which are light brown nuts inside pear-shaped capsules, aren’t prolifically produced here in the north.  Bottlebrush buckeye rarely needs pruning, unless planted too close to the house.  Southern Living’s Steve Bender sums up by stating:  “People often expect the prettiest plants to be a pain to grow, but that certainly isn't the case here. Bottlebrush buckeye needs moist, well-drained soil and partial to full shade. That's it.”

Thursday, July 1, 2021

Let It Be

“Just sit back and watch it grow!” was a favorite line proclaimed by radio talk-show personality Ralph Snodsmith after he dispensed gardening advice to a caller.  The onetime horticultural guru of New York’s WOR-AM, Ralph knew that most plants want to grow if we gardeners just give them the right conditions and care.  But sometimes, a plant will take its own sweet time deciding if it is going to live or make a one-way journey to the compost pile instead.  This has been my experience with a species called Acanthus spinosus, a.k.a. bear’s breech.

Hailing from the Mediterranean, Acanthus spinosus has much to recommend it as a garden plant.  Growing in a large clump, the attractive, dark green, glossy foliage is deeply cut, thistle-like, and only modestly barbed.  It is resistant to insect pests and rabbits.  Spikes of snapdragon-like flowers in shades of pale and dusky pink are distinctive and rise to three feet or more above the leaves.  The ancient Greek architect Callimachus was a fan of this plant, decorating the top of his Corinthian columns with Acanthus leaves, and it still a common design element in contemporary art and design.  Often commonly called “bear’s breeches,” the plant has nothing to do with the slacks Smoky wears or we wish Yogi would put on, but derives from the bear claw-like flower bracts.  Other common names are oyster plant, sea holly and bear’s foot.  Such a historic plant with a dignified demeanor certainly should have a loftier moniker.       

Having seen Acanthus species thriving in warm southern climes, I was surprised to see it living large in Ithaca, New York, as well.  At the time, I had assumed that we were too far north to grow it successfully, but if they could grow it in Ithaca, well by golly, it should grow in Castleton-on-Hudson, too.  So I procured a plant, set it into my nice loamy soil in a backyard spot, and sat back to watch it grow, letting Ralph be my guide.

That was twenty years ago.  For at least fifteen ensuing summers, the Acanthus would produce just a modest leaf or two, never more.  It didn’t look sick, but refused to thrive.  I kept the weeds and neighboring perennials at bay, and watered it occasionally, but the status quo was maintained.  For perhaps a decade I hardly gave it a thought, but I let it be.

In 2016, the Acanthus woke up, becoming fuller and downright lush. I’m not sure what sparked the change:  the mediocre Batman movie, Brexit, presidential politics?  Perhaps that difficult year inspired it to adopt a “now or never” attitude in terms of its own survival.  In 2017, it produced its first flower spike, and this year it sports a half-dozen more, finally making something to see.  I can finally say “I grow Acanthus spinosus” and not be ashamed of my results.

I’m glad I let this late-bloomer do its thing, get it’s grove on and finally rise up singing.  The Acanthus has taught me patience.     

Monday, June 21, 2021

A Green Grand Canyon

Being a plant guy, I can’t help but turn any outdoor vacation into a busman’s holiday.  On a recent trip to the Pine Creek Rail Trail for a 120 mile bike ride, I knew I would enjoy cycling amongst the mountains, seeing the landscape and maybe spotting some wildlife.  I also ended up, no surprise, looking at a lot of plants.  While much of the flora is the same as we see here in the Hudson Valley, it was fun to spot the differences among the wild plants in “the Grand Canyon of Pennsylvania.” 

I was rather skeptical about this loftiest of landscape titles, but Pine Creek does indeed flow through a narrow valley up to 1,450 feet deep; standing on top we were above the vultures and fog.  While a good part of the area is now protected, it is a site of former widespread devastation.  In 1798, the first of the giant trees, centuries old, were felled and sent downstream to hungry sawmills.  Soon tremendous rafts of timber choked the creek.  When the trees near waterways were gone, railroads moved in and climbed up the adjacent valleys.  By the dawn of the twentieth century, the canyon was stripped bare, only thorny brambles and mountain laurel remaining.  Then, in 1903 wildfire swept through, opening the ground up to landslides.  The timber companies made their final profits selling the exhausted land to the state. 

Looking at Pine Creek today, it’s hard to imagine the transformation from hell-on-earth green-cloaked paradise.  Bears, deer and rattlesnakes crossed the trail in front of us, and eagles soared overhead.  River birches, with their flakey bark of gray, cinnamon, and tan, lined the banks of the creek.  They don’t mind life clinging to a streambank or the occasional flood.  Stock-straight sycamores in uncountable numbers grew along the trailbed, their trunks like Greek columns holding up a leafy canopy.  Tulip trees, their show of yellow and orange flowers past but easily identified by their distinctive four-lobed leaves, were another species common in the canyon but rarer in our neck of the woods.  Exotic invasives also call the canyon home, including not a few Norway maples and many acres of Japanese bamboo.  Since I was on holiday, I tried to keep my blood pressure down, but closing one’s eyes isn’t good while riding a bike.

I was especially happy to see rosebay (Rhododendron maximum) growing in its wild state.  The species name “maximum” is a great descriptor.  Rosebay easily grows to ten feet high, sometimes 20 or more, and when its stems collapse, they root and form colonies up to 25 feet across.  The huge, droopy evergreen leaves have been likened to donkey’s ears.  Large clusters of pink buds open to snowy white flowers.  It likes part sun, part shade, damp soil that’s not too wet, and may choose to live on rocks or in swamps.  Creating the right environment for it would be impossible in my garden, so I gave it my regards in Pennsylvania.     

Friday, May 28, 2021

An Onion Grows In Kinderhook

It might have been a dream, but I think I remember an old Jeopardy! episode with the category “Alimentary Alliums.”  In it, Alex asks, “This rare member of the onion family is found on sea cliffs along coastal Cornwall and Dorset” and a contestant volunteers “What is Babington’s Leek?”  Given the scores of edible members in the Allium tribe, an entire Jeopardy game could be dedicated to uncovering the fascinating details of onions, shallots, leeks and garlic.  And let’s not forget chives, Allium schoenoprasum, a plant which taught me that some alliums also have beautiful flowers.

And that is what I’m thinking about today, onions grown not for their culinary usefulness but for their value as “eye candy,” which I call “ornamental alliums.”  Last weekend, I biked through lovely Mills Park in Kinderhook, where a large floral display including perennial blue flax, white narcissus and magenta alliums got me to pull over for a closer look.  Unfortunately, my firsthand knowledge of ornamental alliums is slight, so I won’t be participating in onion-themed Jeopardy! anytime soon.  I therefore won’t hazard a guess as to exactly which allium grows in Kinderhook, but I must say they were impressive.

Many ornamental alliums are described as a large ball of small star-shaped flowers in shades of lavender, magenta, purple or violet.  These round “umbels” are borne on long, thin green stems, with just a few often non-descript leaves at the base.  Allium hollandicum, sometimes called the Persian onion, is a typical of these, growing to between one-and-a-half and three feet tall.  The variety ‘Purple Sensation’ has darker flowers and has earned an Award of Garden Merit from the Royal Horticultural Society in the United Kingdom.  Allium ‘Globemaster’ is a hybrid cross between A. christophii and A. macleanii and is sterile, so it doesn’t spread promiscuously, and grows stems between three and four feet tall with a lavender sphere on top.  Allium giganteum, which unsurprisingly is called the giant allium, boasts softball-sized purple flower clusters on towering stems of five feet.  Despite its grand size, sources say it doesn’t need staking.  While these large-type alliums are individually impressive, one solo plant looks silly, so garden designers say it is best to plant them in groups of at least five to seven. 

More variations abound.  For blue globes of flowers, try Allium caeruleum, which grows to two feet.  Small, egg-shaped purple flower heads on very thin stems characterize drumstick allium (Allium sphaerocephalon).   Turkistan onion (Allium karataviense) has fat, attractive leaves, floral globes of pale pink, and grows only a foot tall.  Lady’s Leek (Allium cernuum) boasts delicate, open flower sprays of white, pink or lilac and, like most ornamental alliums, needs well-drained soil and not wet feet.    Tumbleweed onion, Allium schubertii, grows about two feet high and has a loose sphere of lavender flowers of varying lengths, giving it the bizarre appearance of a firework or space alien.  It also makes a good dried flower.  There are dozens more, providing an ornamental onion for every taste.    

Monday, May 10, 2021

They've Got You Covered

I believe it was Ben Franklin’s gardener who said only three things are certain – taxes, death and weeds -  and we’ll all be pushing up the latter after death.  Abetting weeds is not a comforting thought, so after I’m gone, I hope to be fostering groundcover.  These low-growing plants, often spreading by stolons or rhizomes, can successfully hold the soil in place, conserve soil moisture, increase organic matter and battle weeds – all things I’ve spent a gardening lifetime striving toward.

Let me dispense with some obvious choices first.  Myrtle (Vinca minor) is tough but can get invasive; same for lily-of-the-valley (Convallaria majalis) and carpet bugle (Ajuga), which often ends up in the lawn.  Don’t plant goutweed (Aegopodium podagraria) unless you want only goutweed, everywhere.  Pachysandra spreads politely but effectively, making a virtually foolproof evergreen carpet.  At least in my garden, it gets high praise.

For partial shade, barrenworts (Epimedium species) can’t be beat.  Their patches of heart-shaped leaves spread slowly, with tiny white, yellow or red flowers in early spring.  Wild blue phlox (Phlox divaricata) is a native woodland wonder, with pale blue flowers over a creeping mat of foliage.  The flowers of lungwort (Pulmonaria species) are deeper blue, and the green foliage is splattered with silvery spots.  Thought to cure pulmonary diseases in ancient days, its common name is no marketing asset to today’s garden center industry.  Sweet woodruff (Galium oderatum) has a more cheerful moniker and features tiny white flowers and whorled foliage all on a plant less than six inches tall.  It is said to the basis for Maitrank, the German wine traditionally imbibed on May 1.  Favorites for foliage of similar stature are the trans-oceanic cousins, European wild ginger (Asarum europaeum), with shiny green, kidney-shaped leaves, and Canadian wild ginger (A. canadensis), with a matte finish.  The tiny purplish flowers are so low only the slugs (their pollinators) and extremely curious gardeners can even locate them.  I’ll finish with the wee-est of all, Kenilworth ivy (Cymbalaria muralis), a lilac-flowered crack-filler which used to cover our old brick steps before the mason made them safe again.  It now resides on the greenhouse floor, where rules of horticultural sanitation say it must not remain, although pulling it out is as heartless as throwing an old dog off the sofa.

Need something taller?  Carex morrowii ‘Ice Dances’ looks like a spider plant, with its grass-like leaves edged in white, and makes a mass 18 inches tall.  From the same genus, Carex ‘Blue Zinger’ spreads faster but is a plain, dark green.  At two feet tall, Variegated Solomon’s seal (Polygonatum odoratum ‘Variegatum’) is lovely, with arching stems, pendant flowers and green-and-white leaves all on a tough plant.

In sun, low growing sedums, such as Sedum kamtschaticum, S. acre and S. reflexum survive in the worst soil and provide textural diversity with few maintenance needs.  Similarly rugged is big-root geranium (Geranium macrorrhizum), with pink spring flowers, evergreen foliage and a spicy fragrance.  Of course, don’t forget lamb’s-ear, thyme, catmint, moss phlox – I’ll be an old man before I can list them all.

Thursday, April 22, 2021

Boxwood Back From The Blight

Boxwood, those plush green globes and mini-hedges popular with the highest gardening elites down to the lowliest discount garden centers, fell from grace about a decade ago with the advent of a deadly disease called boxwood blight.  In the early days, photos of giant piles of dead boxwoods culled from nurseries and lush gardens browned by the blight circulated as warning stories.  But what has changed since then?

First, a little review.  Boxwood blight showed up in several east coast locations simultaneously during the summer of 2011.   Like Stonehenge and superconductivity, no one knows its exact origin, but boxwood starting dying of the strange fungus in the United Kingdom way back in the 1990’s.  The first symptoms that occur are light to dark brown, circular leaf spots with dark borders. Infected stems have dark brown to black, elongated cankers. Rapid defoliation occurs, especially in the lower canopy of the shrub.

Disease transmission primarily happens through movement of infected plant material, contaminated landscape and garden tools, and rain/irrigation splashes.  Fungal spores are spread by wind, rain or sprinklers.  Because spores are sticky, they can potentially be spread by contaminated clothing and animals, including birds.  Spores on infected leaves that have dropped can survive five years. Warm and humid conditions cause the fungus to spread quickly.  Gardeners are urged to clean their tools, never water boxwood from above and replace dead boxwoods with something else.  The fungicide recipes and regimes required to keep boxwood green resemble a cross between Baked Alaska and Gateau St. HonorĂ© and are unsustainable.

In terms of dollars and cents, boxwood is a fairly large business, with sales of $126 million annually on 11 million plants, so it’s worthwhile for the nursery industry and government to become involved.  Adversity also inspires genius, and it has gotten some plant pathologists looking for possible solutions in tiny places.  One group of researchers found a bacterium they’ve named SSG for its size and shape (small, sage green) in the leaves of a very blight susceptible boxwood cultivar called ‘Justin Brouwers.’  In laboratory experiments, SSG interrupted the lifecycle of the blight pathogen at several stages and killed blight spores.  When sprayed on diseased leaf litter under boxwood plants, SSG reduced the blight by 90%.  Their conclusion is that SSG “offers great promise for sustainable blight management in nursery production and in the landscape.”  Other biocontrol agents being studied include another bacterium called Pseudomonas and a fungus named Trichoderma.     

But what if you want to buy the most blight-resistant boxwood you can find today?  Scientists at the US Department of Agriculture compiled data from several previous studies to find that answer.  According to their list, Buxus microphylla ‘Little Missy,’ ‘Winter Gem,’ ‘Compacta’ and ‘Green Beauty’ are among the most blight resistant types out of 131 examined.  Before buying, acquaint yourself with what boxwood blight looks like. When shopping read the labels carefully, and examine the plants with even more scrutiny.  After planting, continue to keep watch.  Hopefully, all will remain green.