Who is this guy?
First, a word about the author, because the name Dirr carries a lot of weight in the plant world. This Georgia professor of horticulture has authored 12 books, which seem to become instant classics. But I like that his stature hasn’t stifled his inner ranter, and he gets quoted for assertions like: "A garden without viburnums is like a life without the pleasures of music and art." See, a passionate guy, and that passion and a nice sense of humor are reflected in his writing. Here’s lots more about him.
The challenge faced by Dirr and Timber Press was to produce the definitive book about a large genus of plants that pleases several groups – home gardeners, nursery professionals and garden designers. Well, this home gardener loved the 424 excellent photos of every species that’s profiled, and more advanced readers are treated to detailed breeding notes and other hort arcana, so the result is not a read-through garden narrative but a true reference book.
Putting on my coaching hat, I imagined gardeners consulting the book for advice about the right plant to buy, maybe one that’s especially shade- or drought-tolerant, hardy to Zone 4, or most likely to be available on the market, and here the book might disappoint. The narrative format of the plant profiles requires a whole lot of reading to cull answers like those, and this impatient reader would have preferred little symbols or some easy way to hone in on plants that meet particular requirements.
It’s a big ole genus of plants that come in a wide variety of sizes, some evergreen, mostly drought-tolerant, largely free of diseases, with a "strong trend toward deer resistance", offering both American natives and nonnatives to choose from, so what’s not to love? Exactly – so why is it so little used? I’ve noticed a handful at the largest nursery near me, at the end of bin after bin of rhodies, a plant group that’s much less likely to perform well in Mid-Atlantic gardens.
Dirr’s on a mission to correct the underutilization of these tough but beautiful shrubs, the next logical move in his campaign for woodies as a whole. As a consistent, possibly annoying cheerleader for shrubs myself, I salute him!
Naturally I read the plant profiles for plants I’ve grown myself, and about V. carlesii or Koreanspice Viburnum, Dirr says it does indeed live up to its catalog descriptions, then goes on to the details. That reality check is what I want in a plant book – that and great photos – and this book delivers on both counts.
Both the snowball and doublefile types of V. plicatum are considered by many to be the most gorgeous of all, but I learned recently from an expert near me that they’re the least drought-tolerant of all Viburnums. Wish I’d known that before I bought up a bunch of them because the Great Drought of 2007 caused mine to suffer quite openly. So I was curious to see if Dirr mentioned this and he didn’t disappoint, stating that "consistent drought and high heat result in bedraggled specimens." Yes, bedraggled is a good word. But the point is that Dirr gives readers that in-the-garden reality check.
Care – What I learned
- When examining a potted specimen at the nursery, slip it from the pot and check the roots – the more white roots the better. I did not know that.
- As to pruning, Dirr says that "tidying and shaping with hand pruners is best." Plus, you can shorten (to the nodes) any extended shoots. In hedges, he recommends against using hedge sheers (brown edges can result). Instead, do "feather pruning with a hand pruner". This approach "involves removal of every other shoot, every other year" but "results in a more aesthetic, not-as-blocky hedge." Never heard of such a thing. Will try it.
- As to fertilizing, Dirr says that Viburnums "prosper quite well on a restricted fertilization diet". He feeds his in late winter with the recommended rate of 10-10-10 plus minor elements. "A second application, (one-half recommended rate) can be applied after flowering." Now that wouldn’t be my definition of restricted fertilization diet. I’m more of the mulch-them-and-they-will-thrive school.
- Which fertilizer to use? "Slow-release fertilizers like Osmocote (The Scotts Company) and
Nutricote (Sun Gro Horticulture) are suitable as well, or water-soluble formulations like Miracle-Gro, also from The Scotts Company," with their website URL given. What, no thoughts about whether to use fast-and-synthetic or slow-and-organic?
- I was happy to see this: "Soils enriched with rotted and composted manure and other organic materials provide ideal havens for viburnums and reduce the need for supplemental fertilizer," and he recommends mulches of composted leaves. So I’m pretty sure he gardens like we do – naturally.
Here’s proof that nothing’s a given in the wild world of plants. V. nudum ‘Winterthur’ is labeled as growing to 6′ and that proved to be the case in Dirr’s garden (after he killed the first one he tried, and I love that honesty). But a ‘Winterthur’ at Longwood Gardens grew to 10′. The doublefile ‘Shasta’ matures at 6′ in some places and 12′ in others. Keeps us on our toes.
Questions I Have
- In his acknowlegments Dirr thanked some folks for "making me spiritually and academically whole and persistent." Now that sounds like the beginning of an article I’d love to see published somewhere. Say more!
- What does Zone 7(8) mean, or conversely, (4)5? Sorry if I’m showing my ignorance but I couldn’t find an explanation.
- And about V. nudum Dirr writes that it’s "native to Connecticut, Long Island to
Florida, west to Kentucy Lousisiana, and east Texas. Zones 5 to 9.
Introduced in 1752." If it’s native, what does "introduced" mean? Again, my apologies.
So I pick some nits – that’s what I do – but they pale in comparison to my admiration for this valuable contribution to garden writing, and the author and publisher who consistently produce such good work.
Photos from top: cover art from Timber Press, close-up of V. plicatum snowball-type, long view of V. plicatum ‘Shasta’, and close-up of V. nudum ‘Winterthur’.