Last March, I planted blue forget-me-nots, yellow English primroses, blue pansies, yellow ranunculus, two bags of yellow Asian lily bulbs and variegated English ivy in a large blue pot on the front porch. It all added up to a living floral arrangement that lasted for three months, through frequent frosts and the occasional spring snowstorm.
Even the ranunculus stayed strong, though it is not remotely frost-hardy.
So, what is the trick to growing them outside when temperatures still average in the 20s most nights?
Ranunculus actually performs best where daytime highs are relatively cool. My northeast-facing front porch stays nippy on even on the warmest spring days.
Frost is easily thwarted with a spun polyester frost blanket.
After planting, I stick in two or three decorative garden spikes or a tomato cage, positioning them so that their tops are 6 to 8 inches above the tallest flower.
Then, every night I throw a frost blanket over the whole shebang, securing it in place with clothespins and an elastic bungee cord, essentially creating a temporary nighttime greenhouse.
If arctic temperatures are forecast I add an old blanket or two over the top. Most mornings I remove the cover, but if need be, the protection can be left in place for several days or until the front passes.
This year, when ranunculus made their appearance at the local home-improvement center at the beginning of March, I chose three yellow ranunculus, five blue English primroses and three pots of pale blue Valerie Finnis grape hyacinths, spending a total of $18. (The lilies and the ivy are still in place from last year.)
When I got home I discovered that the potting soil was still frozen solid and had to go to plan B. Instead, I arranged the flowers in tangerine boxes where they spent the next two weeks on a patio table on my covered back porch in the daytime. At night, I took the boxes inside.
By the third week in March the potting soil finally had thawed and I could proceed, first mixing in pelleted long-release fertilizer. If planting lily bulbs, they go in 12 inches deep (they’ll come up and bloom in June). When planting everything else, I tease the roots out of their tight tangle. Covering the plants day and night for a few days after planting eliminates the need for hardening them off first.
The pot needs watering when the soil dries out, which is infrequently this time of year. I feed with liquid fertilizer monthly. Once these spring flowers stop blooming, I pull them out and replace them with summer fare.
In theory, anyway, ranunculus can be dug up and stored dry over the summer, but last year I couldn’t find the tubers. So this year I left them in their pots to make recovery easier.
If you’d like to skip covering your spring arrangement after the flowers are acclimated, eschew the tender ranunculus and stick to frost-hardy English primroses, pansies, violets, snapdragons, stock, sweet Williams and dusty miller, all available now (or soon).
