As a Horticulturist and a plant slut I am always looking for new plants to try. The fact that some, technically, are not hardy is of little concern. The catalogue may say zone 6 but it really means 5 I’m sure. If a plant is listed as a zone 7, well, lots of time we have zone 6 winters so really 7 is just one zone off. Close enough. I’ll take one.
I am not alone in this desire to push the limits of hardiness. I know a lot of people with Zonal Denial. Virtually all my coworkers and many friends as well are afflicted. I’ve long said that if I was gardening in the tropics I’m sure I would be trying to grow maples and beeches. It must be the I-can’t –have-it-so-I-want-it-even-more syndrome. Before I can even tell you about some successes I must confess some failures (it’s the recovering Catholic in me).
Let’s go alphabetical – Acanthus mollis ‘Hollard’s Gold’, Agave parryi, Canna ‘Red Stripe’, Colocasia esculenta ‘Tea Cup’, Crocosmia ‘Eastern Star’ and ‘Walcroy’, Musa basjoo (two in one year and it is a zone 5 but I forgot to mulch), Salvia mexicana ‘Limelight’, some palm tree, and many more I’m sure. There. I feel better.
One of the first non-hardy plants I had success overwintering in the ground was Salvia guaranitica, anise sage. The incredible cobalt blue flowers of this salvia are unsurpassed.
And they bloom from July onward so it’s great color for a really long time. The first couple years I had it in the Southwest Border Garden I dug it in the fall and tried to overwinter it like a dahlia. Dead. They do develop tubers similar to dahlias but I had no luck. Then one year I decided to leave them in the ground and see what would happen. Success! The straight species and the light blue ‘Argentine Skies’ (or is that ‘Argentina Skies’?) have been in the garden ever since.
A few years later we added ‘Black and Blue’ which has proven just as hardy. ‘Black and Blue’ is my favorite because the calyx that holds the flower is black as is the upper part of the stem.
I have friends whose plants are increasing in size annually. An interesting aspect of this plant is it seems to get taller when it comes back from overwintered plants compared to newly planted specimens. So if you want a plant under 3 feet buy new. Also, with marginally hardy salvias it is best to leave the stems alone over winter. If you cut them off the water can run down the stem in to the plant crown. The water freezes and the crown blows apart.
In the Garden for Everyone a Lycoris chinensis (surprise lily, naked ladies) was blooming last week. There’re probably 3 or more plants really but only one blooming. The individual flowers are stunning in their deep yellow color and form sitting atop naked 2 feet tall stalks.
In some catalogues you can find it listed as a zone 6 with “maybe 5” added. Sometimes it is listed as zone 7 and warmer. Somebody suggested we try it so we bought 5 bulbs. Unlike the more familiar Lycoris squamigera, the leaves of L chinensis emerge in the fall. In Indiana that is not the best timing. Winter can be a little hard on foliage. But these plants get enough energy back to the bulb for at least some bloom. I definitely want some for home. The red flowered Lycoris radiata deserves more trialing too (I’ve only killed it once).
Now, back to the Southwest Border Garden where Impatiens omeiana has been flourishing since 2002. This perennial impatiens is listed as a maybe-6. I. omeiana is grown for the foliage, bronzey green with a creamy midrib and veining – absolutely gorgeous. Added interest is provided by the reddish stems and leaf petioles.
The pale yellow flowers come in fall and are interesting but not overly showy. This is a plant more gardeners need to experiment with. My photo from this week doesn’t do it justice. You see it May through July and it’s full-on lust. Check for better pictures on our Facebook page.
Sometimes (okay, more often than not) we discover a plant that is hardy by accident. Well, not accident so much as forgetfulness.
Calla lilies are not considered hardy in central Indiana. And often are not. But in the lower cutting garden is a cultivar called Mango. It has survived 5 winters in the ground and the clumps get a little bigger each year. It had been purchased for a container one year and the next I planted it in the ground. That fall I forgot all about it. In late Spring a leaf started to unfurl from the soil, deep green with white spots. It was ‘Mango’. The white callas I had bought to use for cutflowers weren’t doing so great so I thought, “Why not leave them in the ground too? At least I would get a few blooms”. They died the first winter. Like I said, it’s a gamble. This year I have 3 Eucomis bicolor (pineapple lily) up that were missed in the fall dig. This is the second time we’ve experienced that. My friend Terry had Eucomis ‘Sparkling Burgundy’ self-sowing in her garden a one point.
I’ve had Agapanthus come back once – one out of about 10 plants. At home I had a Phygelius (Cape fuchsia) survive several years. Never would have thought that could happen. And all those plants I listed as failures? Don’t think for a moment I won’t try again. I can keep making believe I’m gardening in zone 7 a long time.
Filed under: Horticulture