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Great Gardening by Sally Cunningham: Hellebores make great perennials

Plantasia, PlantWNY’s garden and landscape show held last weekend at the Fairgrounds in Hamburg, was a great success – a record 15,000 attending. Afterward, as I closed my tired eyes and looked back on it, I pictured creative landscape displays, cool garden decor, outdoor living products and, most of all, plants. Three plant groups stood out in multiple displays and lots of them went home with you. And now I’ll bet some of you wonder what to do with them ...

Succulent city

Succulents have become quite the trend, and they were well represented at Plantasia. Succulents are plants with fleshy, swollen stems or leaves that retain their water and typically live in dry environments. Botanically the group includes cacti, but in horticultural usage “succulent” excludes cacti.

Some succulents are old pals. You probably knew Hens and Chicks (Sempervivens) and sedums long before you could name a coreopsis. The two are hardy perennials that we can grow outdoors here. Other succulents that we frequently use as house plants or in containers are aloe, kalanchoe, agave, echeveria and crassula (jade plants among these). Frankly, for practical purposes, it’s not too important to know succulents’ names unless you are a collector: If a plant is succulent – with fat, fleshy leaves – its needs are fairly predictable:

• Light: As bright as possible, as in desert climates. Avoid sunburn in south-facing windows. If they get leggy, snip off some shoots, remove leaves and root them.

• Dry air and temperature: Humid conditions will wither and rot them. In winter they’d prefer cool nights (close to 60 degrees), but most survive our house conditions.

• Moisture: Water consistently whenever the soil dries out, while they are growing. During the winter rest period, water less, perhaps only every two weeks. They must never become waterlogged.

• Planting mix: Use material labeled for cacti and succulents – lighter than typical houseplant mix.

• Containers: Traditionally grown in stone troughs, they do best in unglazed pots or hypertufa, because these wick away excess moisture.

If a succulent followed you home from the show, show it some sunshine, observe the minimal rules, and it will multiply and possibly even flower someday.

Hellebores

The genus Helleborus is wide and varied, also known as Lenten Rose or Christmas Rose, and there are many outstanding crosses and cultivars. They were always good shade plants, even tolerant of planting among tree roots once they are established, and they spread nicely. Now they have increased in popularity in recent years because of their undesirability for deer browsing (except in desperate situations). Also the newest hybrids have more upward facing flowers as well as larger and longer-lasting blooms. So what’s not to like?

Many hellebores were sold at Plantasia and, as with other perennials that were forced to flower early, people wonder how to keep them happy and alive until planting time outside. Hellebores are easy, extremely hardy perennials, and normally they flower in late winter even in the snow – but they can’t go from a warm building to a freezing porch, so we have to help them adjust. The ideal place to keep them would be a cool room with good light, where they will continue to flower for a long time. Eventually you would cut off the finished flower stems, just as you would outside, and the attractive foliage will last all summer. If you don’t have a cool room, a normally warm room will do. But do not dry these plants out. Water whenever the soil on the top of the pot feels dry.

Planting time then depends upon you and the weather. If you can acclimate these plants to cold nights and cool days – as in an unheated Florida room or greenhouse – you could plant them outside as soon as the soil is workable. A late freeze won’t matter. See how their planted counterparts are plenty tough and keep their leaves nearly all winter. However, if you have to keep these plants in your heated house all spring you might have to wait until May to plant them. Gradual change is the norm to help any plants adapt to new conditions.

Congratulations. You bought a great perennial that will likely be in your garden for many decades. (I have a pass-along hellebore from Peg Thompson of Hamburg that is probably 80 years old.)

Those hydrangeas

Most of the beautiful hydrangeas you saw at the show are called florist plants, gift plants, or undependably hardy big-leaved hydrangeas (Hydrangea macrophylla). That is the same genus from which hydridizers have derived the popular ‘Endless Summer’ and hundreds of other repeat-blooming cultivars, but some are hardier than others, especially when it comes to bud hardiness. When I have explained this florist plant/gift plant business to customers, I have often heard, “Oh, I planted my mother’s 10 years ago, and it’s just doing fine in our garden!” That may be so, as indeed the plant itself may be hardy, but it’s very unlikely that the plant will set bud and keep its buds through flowering. If the above lady indeed saw it flower, I suspect it was covered or placed in a very sheltered, protected place or maybe she planted an actually hardy one.

So – treat the plant like the gorgeous gift plant that it is. The cooler the location the longer the flowers last. Cut off finished flowers or stems, water when needed and enjoy even the richly textured leaves. As much as I am a plant-saver, I wouldn’t plant it outside. Instead, I’d suggest you buy a truly bud-hardy Hydrangea macrophylla (with innumerable improved choices that are so exciting) late this spring – and then hope for a winter-spring of 2016 that won’t kill off those buds. As improved as they are, many of these plants may not flower in June this season. Those who used Shrub Covers or other protections – maybe.

Enjoy your plant treasures from the show and spring plants from garden centers. Spring weather will come, when we and the plants can sing in the sunshine at last.

Sally Cunningham is a garden writer, lecturer and consultant.