Temperamental Perennials

To a new gardener, trying to sort out the annuals from the perennials from the biennials can be hard enough, but when seed and plant catalogs give inaccurate information it makes our work even more frustrating and confusing.

Then there are the hardy annuals, the tender perennials and a relatively new one called temperennials. And of course there are the catalog mistakes and unknowns.In the mistake" category I like to give the example of Althea zebrina, which is also known as Malva sylvestris ‘Zebrina’ and the French hollyhock. I first became familiar with this small hollyhock-like plant at least 40 years ago and purchased it as a perennial. It died. I bought it again the next year from a reputable vendor and again, it died. Neither plant overwintered, and come spring the remains of the previous year's plant simply turned to mush.

Even to this day, many seed and plant catalogs refer to this as a perennial, and yes it is. It’s perennial in Alabama, California and in France. It is not perennial in New York in spite of literature toting it as hardy to Zone 5. Pure and simple, it isn’t.

What does happen, though, is the seed from the plant will drop to the ground in the fall, and the seed is perfectly hardy. Early the following spring the seed germinates and if allowed to grow, the resulting plant will flower later in the summer. This is another clue that this isn’t a true perennial here—because by definition a perennial will flower the second year after seeding and for successive years.

So, a quick review. We sow annuals in the winter or early spring and they flower the same summer and die the same year, usually at the first hard frost. A hardy annual will do the same thing, but its seeds will overwinter and may result in new plants the following season. A perennial is a plant whose seed is planted one year; it then develops foliage or a "crown" and roots during the first year, and it begins to flower the second year.

But a perennial in Peru may not be a perennial in New York due to climate differences. So when this plant is grown in New York it’s considered a tender perennial, and we’re seeing many of these plants used in high-end gardens out here—you can find them at the garden centers as "tender" perennials.

The indeterminate tomatoes … the ones that grow and grow and grow and continue to produce all summer are actually perennials. But they are perennials in South America, where they are native. Up here, though, they die at the first frost. But if they are heirlooms and not hybrids you may find new tomato plants sprouting in the spring—as the seeds, you guessed it, are hardy. So up here this perennial acts as a hardy annual.

The biennials are yet another group that can be a bit confusing. Biennials are seeded one year and they grow vegetatively without flowering. They flower the second year and then die. So biennials are good for only two years.

Well, sometimes. Most hollyhocks are considered to be biennials and yet you can find hollyhock gardens that bloom for years and years without ever planting a new plant. This is because seed dropped at the end of the first flowering year can germinate the following year and flower the next year, setting up a perpetual hollyhock garden even though they are biennials. In theory if you planted hollyhock seeds this year then again next year, you would begin having flowers in the second year and in perpetuity you would have hollyhocks blooming every year so long as you didn’t thin out all of the seedlings in the spring. In theory.

Then there are the temperennials. I started seeing these show up at local garden centers a few years ago and wondered what in the world they were. Turns out that in 2003 Connecticut perennial grower and old friend Pierre Bennerup (Sunny Border Nurseries) coined the phase to describe perennials that were suitable for southern gardens and would be perennial in habit down South, but that acted as annuals up here. In essence, tender perennials with a trade name bound to sell. Walter’s Gardens, the largest wholesale grower of perennials in this country, sells many of these and they’ve become quite popular with local growers and garden centers, so read the labels carefully, as these plants may show up mingled with the true perennials. Walter’s defines them as being hardy in Zone 7 and higher, so they may survive one winter out here but not all.

And for those wanting to take a walk on the wild side, I’d suggest a tour through the Plant Delights catalog (plantdelights.com). There are quite a few plants in this catalog that are completely hardy here and maybe just as many that we could call "marginal." And in case you’re curious, the USDA updated hardiness map has Southampton in Zone 7a, but parts of western Long Island are Zone 7b and Westchester, 6b. To add to this challenge I suspect that some areas of Westhampton to Speonk adjacent to the Pine Barrens may actual be Zone 6b. But remember, that’s a guide, and last winter we were certainly not a Zone 7 and anyone who walked on the wild side and was experimenting with climate change and plant hardiness got a few surprises.

Want to experiment? Hardy sugar cane (Plant Delights #1735) can be a mighty interesting hardy grass up to Zone 6a. Crinum ‘Improved Peach Blow’ is listed as 7a and even Calocasia ‘Jack’s Giant’ is listed down to Zone 7a. Will they make it out here?

Then there is my nagging question about hardy lilies and if they can (or should) be planted in the spring—or should we wait until the fall? I put this question to a number of experienced gardeners last year because the B&D Lilies spring flier arrives in late January and it’s oh so tempting. But traditionally the Asiatics, Orientals and Orienpets and hybrids are planted in the fall just after they are field-harvested. This fall planting allows the roots to establish just before the bulbs go dormant, and the following summer you get a full-sized plant. But over the years these bulbs have become available for spring planting as they have been stored over winter in specially controlled refrigerators–in the case of B&D at their farms in Washington, and for most others in Holland.

B&D (bdlililies.com) has almost 100 varieties available for spring planting, with about 10 of them new introductions, but the question remains: Is spring planting of these bulbs a good idea? As a traditionalist I’d say no, if only because of the stress it puts on the growing plant to establish roots and then flower the same season without a "rest." Then the gardener in me got the best of me last year, and I did plant a few in the spring. As they fairly note, the first year's plants will be a bit smaller than in following years, but they seem to do fine. I’ll reevaluate this summer, when these plants will be in their second year, but, yes, they did flower last year, although the flowering was a little thin and the plants a little small.

Keep growing.

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