For two months out of the year, December and January, my delphiniums let me rest. The remainder of the time, they keep me busy.
Mostly Pacific hybrids bloom their last by late October, and the bulk of their stalks are cut back. November sees the rest of the stalks removed and sand scattered about the crowns whether or not new basal growth has begun.
Sandy Mulch Works Best Against Slugs
The sandy mulch keeps off slugs that love to work their way up for a nibble any time thaw permits for plants in the open borders.
The delphiniums I grow in containers to use on the patio or fill bare niches are insured against slugs by bottom layers of pottery shards.
Container plants get sand for protection from heaving caused by abrupt weather shifts.
Keep The Sandy Mulch Hydrated And Well-Drained
Even frigid cold does the plants no harm, providing they are well-drained, unsoggy yet moist.
If they’re caught bone dry by a sudden freeze, goodbye.
My pots and gallon cans winter in an area by a south wall where they get full sun when they’re not being rained or snowed on, while bigger tubs sit in the lower yard.
We may have a dry November spell here in Utah when watering is in order.
I sometimes pack snow from unmelted banks to heap on dehydrated pots even in December and January.
By snowdrop time in February, crumples of green perforate the sand, some appearing earlier, some never going entirely dormant.
If storms have dissipated the mulch, it must be renewed, or you will go out one bright day and find that a hungry slug has demolished the green.
Should my accessible sand run low, I use vermiculite.
It is equally effective if dampened so it won’t blow.
The crowns mount slowly, standing still when blizzards roar, undamaged except by sleet.
Pieces of wire screen make good sleet shields.
Could one ever know in advance when this enemy threatens?
Pocked leaves are not fatal, however, for others spring up to replace the losses.
A Vigorous Start For Delphiniums
March may act like February’s twin for a time, later imitating April. Suddenly crocuses are out.
#2 – Divide by hand, use a knife or a spade
#3 – Make divisions with 2 or more stems
The delphiniums spurt with energy, making vigorous little clumps. If any are to be moved or divided, now is the time. Then comes feeding.
I use compost or leaf mold for the base, generously mixed with superphosphate and dried manure, adding sulfur dust and chlordane to ward off pests and blights.
The plants respond with climbing spikes, which must be carefully staked.
Before I know it, May is here with the first buds and blossoms.
Ready Flats For Sowing Delphinium Seed
Now comes the hectic interval.
Between watching the fluted florets and trying to decide which lovelier of my two favorites, cobalt ‘Blue Jay’ or shining white ‘Galahad,’ I must ready flats to sow for increase and replacement.
Clump splitting is not the fastest way to build up stock.
The one you want invariably has only 2 or 3 divisions or is too immature to cut apart.
A packet, perhaps a half-packet, will give enough seedlings even if some don’t make the grade.
I find it unnecessary to replant each kind every year.
Planting ‘Galahad’ one May, ‘Blue Jay’ the next, ‘Summer Skies’ if I crave lighter blues, or ‘King Arthur’ for purple tones, works out about right.
This year, I’m varying the program with the Chinese strain.
Delphiniums can be planted from May to August, preferably May, so the seedlings get well started before the summer heat arrives and be husky enough to carry staunchly through the winter by fall.
The flats I use for sowing these and other perennials are made of long-lasting redwood, 12” x 15” x 3” inches.
Over the first layer of drainage pebbles, I do the following steps:
- I spread peat moss to keep soil from washing through, then a 1 ½” inches layer of planting mix—pulverized leaf mold and garden loam seasoned with dashes of fungicide and superphosphate.
- Next comes a slow soak, distribution of seeds over the damp surface, and a ¼” inch sifting of the mix to finish.
- For shading, I like sections cut from old match-stick bamboo curtains.
These let in air and light yet keep the flats pleasantly moist without further watering unless dry and hot weather.
Low peat moss bins on my lath-house floor make a perfect parking space.
Germinating Delphiniums
When germination starts, in about 3 weeks, off come the covers.
The first true leaves, sprouting singly rather than in pairs, expanding fast and should be nourished.
Here are the following tips I do once germination starts:
- Diluted fish emulsion gives the young foliage a real boost.
- If germination is prolific and the flat overpopulated, transplant the most crowded seedlings to another flat or a sheltered bed.
- Pricked out with care and kept moist and shaded, none should be lost.
- Small fiber pots can be used for these early transplants.
- I fill a large wooden tray with the potted infants, let them get settled, then move them to brighter light and freer air circulation.
This is the critical period.
The goal is sufficient water for good soil tilth and enough well-balanced food to keep roots and leaves forging ahead.
All this time, the superb trusses of matured blooms are being admired in the border and patio and lower yard, groomed of spent panicles and re-staked if necessary.
Sulfur dust is applied to the dense under-foliage for mildew prevention.
Blooming Seasons Of Delphiniums
I often read that delphiniums have two blooming seasons.
Mine doesn’t stick to a schedule.
Some are just beginning to flower as others finish.
The finished ones, cut back and lavishly fed, produce fresh blossom crops as the tardies wind up and get their pruning.
Continually, from May to October, bees can find the ruffled spikes.
Hummingbirds come sipping, too.
Fall Is Moving Time For Delphiniums
Meanwhile, back to the flats of pushing youngsters, I am busy preparing beds and containers and assembling soil mix.
Cooler days of late September and early October are perfect for moving the little chaps, some with white rootlets already kicking through the peat pots.
I give them whatever shelter is necessary until they dig in, and they will carry through the winter as sturdily as adults.
Now and then, one of either age group will disappear for no discernible reason, but it is scarcely missed from my burgeoning wealth of delphiniums.
When another spring presents increasing glory, I am always glad for my diligence.