APRIL GARDENING CALENDAR

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APRIL GARDENING CALENDAR

Our picture today is a photograph of a green-edged auricula primrose.  As a whole, the auricula section of the genus Primula is fascinating, diverse, and quite varied in form and color.  A hundred and fifty years ago auricula primroses were extremely popular plants in Europe and America.   April is their prime bloom time!  

GENERAL APRIL GARDENING CALENDAR

Finish pruning and grafting of fruit trees if not already done.  Plant grapes and other fruiting perennials, shrubs and vines; fertilize and prune raspberries and blackberries.  Start many flowers inside for transplanting out and direct sow the last hardy annuals.  Direct sow many vegetables late in the month and into May.  April is characterized by ups and downs in temperature—watch for frosts!  Protect frames at night and admit air daily.  Place row covers on newly transplanted, slightly tender plants. 

VEGETABLES

If not done already, sow indoors, for transplanting out early in the month: basil, cabbage, celery, tomatoes, broccoli, cauliflower, kohlrabi, head lettuce, artichokes, Brussels sprouts, Asian cabbage, leeks, greens.  After the 15th, sow watermelon, cantaloupe, squash, pumpkins and cucumbers into peat pots for easy transplanting. 

Direct sow these outdoors once weather permits and soil temperatures are above 45 degrees:  beets, arugula, carrots, caraway, celery, chervil, chives, cilantro, dill, fennel, thyme, oregano, sorrel, collards, mache, fava beans, cress, Jerusalem artichokes, kale, kohlrabi, cabbage, cauliflower, leeks, lettuce, mustard greens, rhubarb, turnip greens, onions, parsley, parsnips, peas, potatoes, radishes, salsify, scallions, spinach, Swiss chard.  Sow corn (after the 20th).  

Harden-off vegetables in frames, or by exposing them outdoors a few hours at a time.  Transplant the following hardy vegetables outside around the middle of the month (they can take some light frost): asparagus, broccoli, cabbage, cauliflower, Chinese cabbage, endive, leeks, lettuce, onion sets and plants, Asian greens, parsley.  

FLOWERS

Sow indoors April 1 for transplanting out: Chinese asters (Callistephus), cerinthe, celosia, craspedia, calendulas, annual centaurea, cleome, cosmos, cynoglossum,  eragrostis, Panicum, Pennisetum, and annual grasses.  Late in the month: sow zinnias indoors. 

Direct sow outdoors all month: annual alyssum Lobularia maritima), bupleurum, carnations, pinks, sweet Williams, cynoglossum, stocks, rose campion, wall flowers, lychnis, lupines, lavateras, columbines, valerian, polyanthus, auriculas, Canterbury bells, hollyhocks, honeysuckles, rockets, honesty, fox gloves, snapdragons, sweet peas, poppies, larkspur, cornflowers, nigella, lavatera, poppies, valerian, kiss-me-by-the-garden-gate, dill, morning glory, sweet peas and wildflowers.   

Weed and clean borders.  Divide perennials early in the month: carnations, bellis, achilleas, asters, mums, campanulas, centranthus, coreopsis, dicentra, dodecatheon, echinops, euphorbias, gauras, gaillardias, gentians, helianthus, hellebores, daylilies, heucheras, hostas, lobelias, papavers, oenotheras, phlomis, monarda, liatris, and marrubiums.  

Start dahlia tubers this month and make cuttings if possible. 

Shade auricula primroses from intensifying spring sun.   This is when auriculas need the most water, but remember— never waterlog the compost.  The month of April is their peak bloom period and hybridizing can take place now.  Shows are held this time of year. 

FRUIT

By April 15, finish pruning /grafting/planting fruit trees; spray Bordeaux mix on fruit trees suffering from fire blight; check fruit trees for pests.  Spray superior oil on dormant trees (before leaf out).  Lime-sulfur will control anthracnose or blight on raspberries if applied when the buds first show silver, or on currants and gooseberries at bud break.  Wait three weeks if you decide to spray lime-sulfur (use caution) as a fungicide on roses, lilacs, dormant shrubs, fruit trees, evergreens. 

Weed fruit trees, strawberries, cane fruits.  Set out apple pest traps two weeks before bud break.

TREES, SHRUBS AND ROSES

Lay out lawns by either direct-seeding or purchase turf and roll it out.  If the weather gets windy and dry, water your new lawn frequently. 

Finish transplanting roses and other shrubs (the earlier the better).  Prune established roses after severe frosts.  Cut out all dead and crossed wood, and seal the cuts with water-based glue to prevent the drilling wasps from destroying canes.   Dress rose plants with Epsom salts, wood ashes, compost, manure, alfalfa meal, bone meal, kelp meal, bunt earth, spent hops, etc. , but keep fertilizers 2 inches away from the canes at the base of the plant.  

 

 

 

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AURICULA PRIMROSES

When we think of primroses, the first thing that comes to mind are the ‘Pacific Giant’ hybrid primroses we see in garden centers.  Actually hundreds of species of Primula are in existence, and some species have been brought into gardens and significantly developed.  The auricula primroses, members of the species P. auricula, have been grown in gardens since the 1500s.  They have evergreen leaves that curl around in a way that resembles the ear of a bear.  When first cultivated, they were called ‘Bear’s Ears’.  Charles l’Ecluse (known as Clusius) is the first person known to have grown auriculas in a garden.  This was after 1573; he grew two kinds.  The first auriculas grown in England are illustrated first left above, in a woodcut from Gerard’s Great Herbal of 1596.  By 1639, at least 15 different colors and even striped forms were grown.  Auriculas were a popular plant beginning in the early eighteenth century when keen collectors began to grow and exhibit them in competitions.  These growers were called ‘florists’.  Several specialized classes of auriculas came into existence over the following centuries.  Potted plants were (and still are) exhibited in flower on black painted shelves in a stage-like display.  The black background highlights the beautiful colors of the flowers.  Auriculas do have an extremely wide color range, much greater than practically every other kind of flower.  The second picture shows a tawny-colored auricula, a color popular in the 1600s.  Auriculas were extremely popular in the nineteenth century, but curiously, are not well-known today.

Auriculas are native to the Alps and prefer gritty, moist, well-drained soil with a good amount of humus.  They are tolerant of alkalinity and extremely winter hardy to USDA climate zone 3, or even zone 2 if covered with snow all winter.  This means they are perfectly suited to growing all over Montana.  They are shade plants, especially when grown at lower altitudes.  The individual plants are small, only about 8 to 12 inches tall when blooming.  The engraving third from left depicts a garden auricula from 1908.  A gardener must watch that vigorous neighboring plants do not overtake them.  Being evergreen, they grow rather slowly.  I found that a mulch of sharp grit, about the diameter of turkey grit, is excellent for them and will discourage slugs.  Auriculas thrive when grown organically and enjoy soil amendments such as bone meal, composted manure, kelp meal, wood ashes, and grit for excellent drainage.

The classes of exhibition auriculas are usually grown in pots and are smaller and less vigorous than garden auriculas.  The pots used to grow them are taller than average, as the plants have a long tap root.  Growers commonly use an organic soil potting mix with added grit, bone meal and wood ashes.  Grit is especially important for drainage, but also for itsmineral content.  Indeed, the flowers have a wonderful mineral-floral fragrance unlike any other.  The last picture above shows a double exhibition auricula.

Auriculas are available from specialist growers as plants or seed.  I grow mine from seed planted in a fine, fast-draining seedling mix, covered with glass and placed in a shaded cold frame.  I plant seeds in late fall or winter, so the seeds have a cold period before they sprout in the spring.  The plants are usually large enough to pot on by midsummer.  Mature plants are best divided  midsummer.  I would urge gardeners to try auriculas; they are beautiful and rewarding to grow.  If grown in the garden, they might be best appreciated in raised beds, where their delicate flowers can be observed.