There’s nothing like the smell of sweet violets in late winter and early spring. But the regular species in our climate is nothing less than a thug. It seeds and grows where you really would rather not have it. Well, forget that. Enter this exquisite fully double flowering Parma Violet. The rich violet blue flowers appear on long stems from January to April. Parma violets are the Mediterranean form of V. odorata and they are less hardy to cold and not so rampant. This form we have never seen set seed- but there are always exceptions. Very glossy green foliage frames the flowers well. Excellent in containers in an unheated greenhouse, conservatory. In the garden choose a protected spot (under evergreen shrubs for example) and give this violet rich soil with regular summer moisture. Tolerates full sun but looks better with some shade. Flowers tend to lean horizontally, they are great for cutting and making little fragrant winter posies. Spreads by runners to form a nice patch in time. Tolerates summer drought when established.
Biome: Dry Shade
Dry shade offers a particular challenge to PNW gardeners. In fact, it can be the hardest location to satisfactorily grow plants. Many gardeners have dry shade, a tall canopy of Douglas Fir or Oregon White Oak or even neighborhood street trees that can conspire to rob plants not only of light but water as well. And to complicate matters, the more you irrigate dry shade near trees the more tree roots you get and the more competition for your lovelies. The solution is to depend on plants that have these three adaptations: dry tolerance, root competition, low light conditions.
We’ve amassed a list of plants that really will thrive in these conditions. A good deal of these plants are native to the forest understory in Asia, they are built for serious competition with Bamboo. Many of our very best dry shade plants are from the Pacific Northwest and already inhabit dry woods. Invite these plants into your garden, they play an important role.
Prepare the soil as you would any rich perennial border. Add and incorporate compost and mulch. Give each plant a handful of all organic fertilizer to speed root growth and establishment and water faithfully for the first season. In these conditions an annual application of mulch is not obscene and will reap great rewards. In time you can water much more infrequently.
Climate Adapted Plants for Gardeners in the PNW
Yerba de Selva or whipple vine, a wonderful small scale evergreen native ground cover. Related to Hydrangeas but this trailer is actually very aromatic with a sweet penetrating aroma if you disturb the foliage. In late spring clouds of small white flowers have the same perfume. Scrambling plant to about 8″ tall and 2′ wide. Full sun to considerable shade. From Portland south this is a common understory component of the herb field. It grew happily in our back 40 where I grew up. There it made pretty scrambling patches between Vancouveria, snow berry and hairy honeysuckle. Often you would see our native columbine ( Aquilegia formosa) as an associate. Its very drought adapted when established but it improves with a few soaks over summer- never perpetually wet and never hot and wet. Otherwise an easy native that should be grown a lot more. Just the fragrance of the foliage endears it to me. For use as a small scale ground cover plant on 10″ centers. It will also gracefully trail over rockeries and walls. Butterflies adore the flowers. Competes well with invasives. Some deer resistance. It may be cut back in early spring to refresh. Once native in the Portland city limits. Oregon native plant.