Wyoming, known for its dramatic mountain ranges and wide-open high plains, offers a unique and often challenging environment for cultivation. Successfully growing plants here requires a strategic approach that acknowledges the unforgiving combination of high elevation, arid conditions, and highly variable weather. This guide offers a framework for selecting viable plants and employing specialized methods to achieve a successful harvest and thriving landscape in this demanding region.
Understanding Wyoming’s Growing Environment
The foundation for successful planting in Wyoming is a clear understanding of its distinct climatic limitations. The state is spread across USDA Plant Hardiness Zones 3b through 6a. Most residential gardens fall within the colder Zones 4a to 5b, necessitating the selection of deeply cold-hardy flora capable of enduring extreme minimum winter temperatures. Compounding the cold is the high elevation, which intensifies ultraviolet light exposure, stressing plant tissues and increasing water loss.
A major constraint for food production is the drastically short, frost-free season, which can be as brief as 60 to 100 days in many areas. This limited window means that only fast-maturing crops can reliably complete their life cycle before the inevitable return of frost. Additionally, the state’s semi-arid, continental climate features strong, persistent winds and low annual precipitation, which rapidly desiccate both soil and foliage. Plant selection must prioritize resilience, speed of maturity, and tolerance for intense conditions.
Successful Annual Vegetables and Fruits
The short growing season demands an emphasis on cool-weather and quick-maturing annual vegetables. Root vegetables are highly reliable, as they mature quickly underground:
- Carrots
- Beets
- Radishes
- Potatoes
Leafy greens like spinach, leaf lettuce, and kale thrive in the cooler temperatures and intense light, often allowing for multiple successive plantings throughout the summer. Cabbage, broccoli, and cauliflower are also excellent choices, provided gardeners select specific short-season varieties that can form heads rapidly.
Many successful annuals are best started indoors several weeks before the last expected spring frost to gain a head start. Certain warm-season crops can be grown successfully by choosing varieties with short “days to maturity,” such as the ‘Early Girl’ tomato. For small fruits, perennial rhubarb is an excellent choice, as its cold hardiness allows it to survive the winter and produce reliably each spring. Raspberries and strawberries are also cultivated, with the latter often benefiting from the protection of straw mulch during the coldest months.
Hardy Trees, Shrubs, and Perennials
Long-term landscape success relies on selecting woody plants and perennials that can withstand the intense cold and wind. Native trees like the Quaking Aspen are popular for their fast growth, white bark, and tolerance for Wyoming’s climate. Evergreens provide structure and year-round color, with species such as the Ponderosa Pine and the Colorado Blue Spruce being particularly rugged and drought-tolerant once established. Smaller, resilient trees like the native Chokecherry provide seasonal interest with flowers and edible fruit.
Resilient shrubs and flowering perennials form the backbone of a low-maintenance, high-altitude garden. Lilacs are a dependable choice, known for their fragrant flowers and tolerance of alkaline soil conditions. Shrubs like Rocky Mountain Juniper and Serviceberry are excellent for windbreaks and privacy hedges, offering dense foliage that holds up against persistent winds. For perennial flowers, species like Daylilies, Peonies, and Iris are consistently successful, returning each year despite the harsh winters. High-altitude perennials, such as Delphiniums and Alpine Asters, are naturally adapted to the intense sun and cold, often having thick stems to resist high-speed winds.
Essential Techniques for High-Altitude Gardening
Standard gardening methods often fail in Wyoming, making specialized techniques necessary to mitigate environmental challenges. Soil amendment is a primary concern, as native soils are frequently alkaline, low in organic matter, and deficient in nutrients. Adding copious amounts of well-aged compost or other organic material annually is required to improve soil structure, nutrient availability, and water retention. Where soil pH is high, incorporating peat moss can help slightly acidify the planting medium.
To maximize the short growing period, gardeners must utilize season extension tools, often starting seeds indoors under grow lights up to eight weeks before the last frost. Simple structures like cold frames, hoop tunnels, and row covers provide temporary protection from late spring and early fall frosts, effectively lengthening the season by several weeks. The use of raised beds is highly recommended, as they allow the planting medium to warm up faster in the spring. Establishing a physical windbreak, such as a sturdy fence or dense row of shrubs, is necessary to protect plants from physical damage and excessive moisture loss.