Begonia grandis in a private garden near Baltimore, Maryland
I'm just back from attending the Perennial Plant Association (PPA) national symposium in Baltimore, Maryland. I've only recently joined this organization, having been talked into it by my friend Janet Draper. And I'm so glad she did! I just spent an amazing, exhausting, energizing 5 days of talks, garden tours, trade show, and best of all, spending time with several hundred fellow plant geeks, including at least a dozen people I already knew from Facebook but had never before met in person. I took over 500 photos, and it's going to take a while to get them processed and uploaded to my Flickr account. For now I'll just quickly share some photos of the first plant (of many!) that blew me away: Begonia grandis, a.k.a. "hardy begonia".
Begonia grandis, leaf undersides
This was a large colony of the species in a private garden that was on one of the tours, growing on a steep hillside in full shade.
Not only was the colony large, but the plants had the biggest leaves
I've ever seen on this species. The above photo is a bit deceptive due
to forced perspective, so the photo below gives a better idea of just
how big those leaves were. The plants were just beginning to bud up, and I would love to go back later and see it in full bloom!
Full shade, consistent moisture, and plenty of room to spread seem to be key. This is a plant that forms large colonies, propagating itself clonally by small bulbils that drop from the leaf axils in the fall, and can easily choke out smaller and less aggressive plants. In my own garden I have several different selections of this species, including a couple of my own hybrids,
growing in various places, some happier than others. I rarely get
leaves anywhere near as big as the ones in the above photos, probably because most of my plants are getting too much light and all of them are getting too little water.
Begonia grandis in my own garden
Begonia grandis 'Early Bird', my first begonia hybrid
Like many shade-loving plants, Begonia grandis can tolerate sun in direct proportion to how much water it gets... to a point. I've seen this species described as "drought tolerant" and when well-established, and growing in full shade, it's true that this species will
tolerate a wee bit of drought but it will register its unhappiness. If it gets any direct sun when dry, and if it gets hot mid-day sun ever, it will go crispy very quickly.
Begonia grandis (white flowered form) showing the effects of too much sun
Now imagine those plants, at the very top, with silver-speckled foliage. Seedlings of B. grandis have silver speckles but they're lost as the plants mature. There's a new wild collection of the species that retains this juvenile speckling, most strongly on the earliest spring foliage. 'Nanjiang Silver' is a somewhat weak-growing plant, and not very tolerant of summer heat, but that single trait has great promise for introducing more ornamental foliage into an old favorite. I've had a bit of luck crossing 'Nanjiang Silver' with standard B. grandis and while the hybrids aren't quite what I'm looking for yet, they're already showing the same colonizing tendency as the species.
Begonia grandis 'Nanjiang Silver'
Begonia grandis 'Nanjiang Silver', flowers and late-season foliage
Begonia grandis, unnamed hybrid with speckled foliage
Begonia grandis, growing where it wants to grow
For more photos from the PPA symposium, please visit my Flickr album (and keep visiting back because it's going to take a few days to get them all posted): Perennial Plant Association