Today the polyantha primrose is the best known, most permanent, and even-tempered of the primula tribe.
Our present-day strains have resulted from crossing the common English primrose, Primula acaulis, with the cowslip, Primula officinalis.
At the current rate of development, the polyantha forms will have an entirely new look within 5 to 10 years.
Thousands Of Polyantha Primroses
The most exciting locale to preview this new look is Capitola on Monterey Bay in California. Here, glowing in the warm sunlight, their spicy odor blending with fragrant mimosa, is a planting of 150,000 polyantha primroses.
Few plants can boast the broad range of colors—white, salmon blends, pink, rose, crimson-rose, violet, blue, yellow, orange, bronze, flame, scarlet, and dark red.
For the gardener who likes to plan definite color effects, this primrose provides a complete painter’s palette with unlimited possibilities for colorful garden pictures and interesting designs.
A variety of flower forms lend interest to a large planting. The florets of one plant may be smoothly flat with the regularity of petals; on another, there may be delightful ruffling and deeply imbricated petals. Double forms are grown, but these do not have the graceful appearance of the single or ruffled forms.
These characteristics will mark the polyantha primrose of the future: a huge, rounded umbel of numerous, very large, firm-textured florets, each held firmly in position by strong short pedicels, the umbel supported by a heavy stem of good height and set off by lush, heavy foliage.
One of the most interesting “breaks” of recent years has been the development of a definite pattern surrounding the eye, giving the flower a true auricula appearance.
When this pattern, now most evident in the violets, is spread throughout the color range, the new look will be fixed.
Cultural Requirements
Knowledge of the natural habitat of these plants will increase your success with them in the garden.
Cool soil with constant moisture under the light shade of deciduous trees is ideal. The use of various mulches will help to achieve this condition.
Polyantha primroses are voracious feeders, and to produce show-quality umbels, the plants must have enough nourishment.
A good medium loam, with thorough bottom drainage, liberally laced with well-rotted cow manure and side-dressed in early spring with a complete fertilizer will provide the necessary vigor. Never allow the plants to lack water.
Under favorable conditions, the plants will form numerous crowns, quickly depleting the soil.
Vigorous plants should be divided every two or three years immediately after flowering. At that time, the plant should be lifted, soil shaken from the roots, and the newly formed crowns severed or broken from the old rootstock.
The roots are removed completely by cutting with a sharp knife 2” inches below the rootstock. Reducing the roots will force the heavy anchor roots to break into many fine-feeding roots.
Lastly, old foliage is best trimmed to allow new leaves to form. The new divisions should be planted in well-enriched soil or a cold frame and constantly kept moist and shaded until roots form.
Raising Primroses From Seeds
Plants in abundance may be raised from seed, which germinates readily in 14 to 21 days. The seed should be sown in a cold frame with shaded glass or a plastic cover to secure the strongest, heaviest-rooted seedlings.
Such protection will prevent fatal surface-drying from wind before germination and conserve the necessary humidity.
Seed may be sown as it ripens in June or July or held over until March for spring sowing. In cold climates, seedlings are wintered in cold- frames or planted out and mulched with salt hay, old cow manure, or peat moss to prevent heaving.
Foliage should be maintained in an emotional state throughout the growing season.
Controlling Pests and Diseases
Black spots, surrounded by a yellow area, may eventually cover the entire leaf, reducing the plant’s vitality.
A combination spray of Bordeaux mixture with lead arsenate, applied during the season, especially in early spring, will control this bacterial leaf spot and all chewing insects.
Green aphids, red spiders, and two-spotted mites may be controlled with regular spraying of Isotox.
Complete control against insects is the best insurance against several little-known but deadly virus infections since insects carry the virus from one plant to another.
Where To Plant Polyantha Primrose
An imaginative gardener will find many places suitable for planting polyantha primrose.
Of course, they are always pleasing when used as fillers for beds of spring-flowering bulbs, but they are also effective when massed in semi-shady locations with a background of fern fronds or broad leaved evergreens.
The gnarled branches of an old apple tree are complementary when In blossom and afford cooling shade from the hot summer sun when the leaves have formed.
If you are a patio gardener, pot several dozen polyanthus and group them with a suitable backdrop for a dramatic pictorial effect.
Breeding Primroses
You can become a working partner in creating new colors and forms by cross-pollinating selected parents. You will not need a detailed knowledge of botany for home hybridization. You may need to know these terms, however.
Plants are said to be pin-eyed when the stigma protrudes above the floret and thrum-eyed when the stigma is obscured in a well below the petal surface.
Pulling the petal in half will reveal the stamens in both types. The stigma is most receptive when slightly syrupy, and the pollen when ripe and powdery.
The blooming of your first batch of seedlings will surely commit you to the most exciting hobbies.
Each spring will have a new meaning when you walk among your “children” under the fresh greenery of flowering trees while the song sparrow trills overhead.
44659 by D. Todd Gresham