boxwood topiary and growth regulators

Happy winter, all!! Its properly cold and snowy out here on the rocky coast of Maine. Hope this is finding you well.

I bought some boxwoods at a southern (Massachusetts!) nursery this fall and brought them up here to over winter in the root cellar. They'll be planted in containers and brought back inside each winter because they are not hardy up here (well, not reliably).

I'm pruning them into rather precise spherical forms and would like them to stay that way for as long a time as possible (understanding that they will need constant shearing no matter what).

Does anyone have experience using a growth regulator on them towards this end. Any advice?

Thanks!!
Karl

The only effective growth regulator is a good sharp pair of shears ;-)

Resin

Well, perhaps you're right but I'm still holding out. Perhaps if I microwaved them?

I wholeheartedly recommend the hedge shears made by ARS. They are very easy to sharpen and hold their edge a very long time. The Japanese do seem to have a knack for making good cutlery.

You'd just get some boiled box ;-)

Very right about Japanese steel, our best carving knife is Japanese. It isn't something recent, either, way back when, European swords weren't a patch on Japanese Samurai swords.

Resin

Depending on the type of boxwood, you probably won't have to do much shearing each year once the form is established. Most boxwoods have just a spring and maybe a lesser midsummer growth spurt. I find that they need much less attention than other topiary plants such as yew and especially juniper. What variety did you get?

I believe it was 'Winter Green' ('Gem'?). I just got whatever looked good at the nursery on the day that I was there, The leaf was a bit more course than I'd have liked but at least I got 6 good specimens.

If you have either 'Wintergreen' or 'Winter Gem', you have two of the most hardy boxwoods for your area, known to do well into Zone 4. Also, both will grow smaller and slower than in warmer zones. 'Wintergreen' will usually grow up to 5' x 5', but in colder zones only 3'-4' x 3'-4'. 'Winter Gem' is even smaller growing, only to 2' x 2'. So, you won't need to worry about lots of pruning and they make for great topiary.

If you can get them, more attractive varieties (deeper green leaf color, nice texture, and better winter color of leaves) include 'Green Velvet' (4'x4') and 'Green Mountain' (5'x3') as well as 'Green Gem' (2'x2') and 'Chicagoland Green' aka 'Glencoe', (2'x3' and faster-growing), all hardy to well below zero and with less winter-bronzing of the foliage.

Boxwoods are great plants. Good luck.

Perhaps it is the 'Winter Green' then because it certainly looks like a plant that could be 5' x 5'. I've pruned them into 18" spheres with the plan that they'll stay around 24". I doubt that'd work with something planted in the ground but in pots with an annual root pruning to boot, I'll either exhaust them into submission or deaccession.

Regardless, thank you for all of the other information regarding the hardier Buxus. It'll come in handy.

Let me chime in -

Several years ago I took four 1 gallon "Winter Gem" plants ($5 at Home Depot) and planted them in large pots on my patio as 'accents' among the furniture. I trimmed them in ball shapes and let them gradually grow to approximately 18" in diameter.

I trim about 3-4 times during the growing season. In October or early November, I lift them out of the pots and plant them in an annual bed. I dig a trench, line it with mulch, and set them in for the winter.

I fill around them with mulch and ignore them until late April or May (this year I dug them up May 10), when I put them back in their pots and give them a good dose of root stimulator.

Each winter they survive our zone 5b vagueries and look none the worse for the experience.

LeawoodGardener: If your terracotta pots are "frost proof" you can probably leave the boxwoods in them and set the whole thing in the ground. I've had a small boxwood potted in a frost proof pot that has frozen solid for the past three winters with no harm whatsoever. Boxwoods are remarkably hardy!

Unfortunately, my large pots are the old-fashioned heavy clay from Italy. I can't even leave them outside in the winter because they disintegrate.

We have a root cellar and I put the ones that I made last year into the root cellar, pots and all. I think that LGardener's approach might help with the root zone and disallowing as much girdling.

In any case, thanks all for your in put.

Karl