Salix prolixa aka Mac Kenzie's Willow

Salix prolixa is a deciduous shrub typically 1–5 metres tall with lance-shaped to pointed-oval leaves up to 15 cm long, hairless and waxy on the underside. Like other willows it grows rapidly in suitable moist conditions. Wide stipules at the base of each leaf are a distinguishing identification feature.

MacKenzie's willow is native to western North America, ranging from Alaska and north-western Canada south to the high mountains of California and Utah. It naturally occurs along riverbanks, springs, seeps, and marshes throughout this range.

Salix prolixa thrives in consistently moist to wet conditions and is most at home in riparian and wetland settings. It tolerates standing moisture and performs best when soil never fully dries out. Drought conditions are poorly tolerated.

Willows including Salix prolixa grow in a wide range of soil textures from light sandy to heavy clay. A mildly acidic to neutral soil pH is preferred. Consistently moist or wet conditions are essential; full sun is required and the plants cannot tolerate shade.

Salix lucida, a closely related North American willow, is rated UK hardiness zone 2 (fully hardy), and Salix alba tolerates USDA zones 2–8. MacKenzie's willow occupies cold montane and subarctic habitats from Alaska to Utah, indicating excellent cold hardiness in temperate to boreal conditions.

As a deciduous shrub, MacKenzie's willow drops its leaves in autumn and enters dormancy over winter. The main growing season runs spring through summer, when the rapid growth characteristic of willows is most pronounced. Catkins appear in spring before or alongside leaf emergence. No special winter protection is needed within its hardiness range.

Salix prolixa is dioecious, bearing catkins on separate male and female plants. Flowering occurs in spring, around April to May based on closely related North American willow species. The catkins attract pollinators including bees and butterflies.

Salix prolixa is exclusively an outdoor plant suited to moist to wet sites in full sun. It is well adapted to streambanks, pond margins, and boggy ground. The aggressive root system can damage underground pipes and drains, so siting away from built infrastructure is important.

Willows respond well to coppicing and hard pruning, which stimulates vigorous new growth of flexible stems. Pruning is best done in late winter or early spring before new growth begins. For ornamental stem effect, stools can be cut back annually or every few years.

Willows are among the easiest woody plants to propagate. Hardwood cuttings taken in late autumn or winter root readily when inserted directly into moist soil. Even substantial stem sections can be used as stakes that will root in place. Seed is viable but short-lived and requires immediate sowing on moist substrate.

Willows are susceptible to various fungal diseases including willow scab, rust, and powdery mildew, as well as aphids, caterpillars, and gall-forming insects. Seedlings can spread aggressively in moist environments and are difficult to control with herbicides once established.

MacKenzie's willow is dioecious and insect-pollinated. The spring catkins attract bees, butterflies, and other pollinators.

The inner bark, leaves, and young shoots of willows (including Salix prolixa's close relatives) are technically edible but have a pronounced bitter flavour. The inner bark can be dried and ground into flour as an additive to bread, but is considered a famine food of last resort rather than a culinary ingredient.

Willow bark contains salicin, a compound that converts to salicylic acid in the human body and has analgesic, anti-inflammatory, antipyretic, and astringent properties. Traditional uses across the Salix genus include treatment of fever, rheumatism, arthritis, gout, and headache. Because salicin is chemically related to aspirin, concurrent use with aspirin-like drugs should be avoided, and use during pregnancy is not recommended. Bark poultices have also been applied to sores and wounds.

Willow stems are prized for basketry and weaving due to their flexibility. Bark decoctions have been used as a hair wash. The extensive root system makes willows valuable for streambank and soil stabilisation and erosion control. Willows also function as dynamic accumulators of nutrients, and have been used to produce charcoal, paper, and timber. Living willow structures such as fences and sculptures can be created from cuttings planted in situ.

Mac Kenzie's Willow requires a bit more attention and knowledge to thrive, making it a suitable plant for those with some gardening experience.

Mac Kenzie's Willow requires abundant, bright and direct light. Placing it less than one foot from a window is the best way to make sure the plant receives enough light to survive and thrive. Depending on your region, however, the current weather can affect the placement of the plant in your home. For example, in some areas the sun may be too direct and intense, so it's best to place it farther away from the window. You may also need to adjust your placement according to the season as the sunlight can change intensity over the course of the year. If you live in a region with significant temperature fluctuations, such as a desert, you may need to place the plant a bit farther away from the window to avoid extreme heat or cold. With some care and attention, your Mac Kenzie's Willow will be sure to bring you many years of beauty and enjoyment.

Ploi's records do not contain confirmed information on the toxicity of this particular plant. In the event of accidental ingestion of plant material with questionable toxicity by you, a family member, or a pet, it is always a good idea to consult a healthcare professional.