Borage in Zone 4B — Mountain West

Borage is a fantastic addition to any Mountain West garden. The cucumber-flavored leaves and beautiful blue star-shaped flowers are edible, adding a unique touch to salads and drinks. Plus, it attracts pollinators like crazy, boosting your other crops in our short growing season.

Our high altitude, intense sun, and alkaline soil can be tough on some plants, but borage handles our conditions pretty well. With a little planning, you can easily squeeze in a crop of borage during our 128-day growing season.

You can transplant borage seedlings outdoors from early to late May after the danger of hard frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense sun and cool nights we often experience.

Space the plants 12-18 inches apart to allow for good air circulation. Keep an eye on the weather forecast, as late frosts or even hail can still occur in May. Be prepared to cover your young plants if needed.

Direct sowing is the preferred method for borage, as it establishes quickly and easily in our Mountain gardens. Sow seeds from mid-May through mid-July, once the soil has warmed up a bit. Borage germinates best when soil temperatures are consistently around 60-70°F.

Prepare your planting bed by loosening the soil and amending with compost. Plant seeds about ½ inch deep and 12-18 inches apart. Keep the soil consistently moist until germination, which usually takes about a week. Borage is easy to direct sow, and it readily self-seeds, so be prepared to have it pop up in unexpected places!

Borage needs moderate watering, especially during our dry Mountain summers. While it's an easy-going plant, consistent moisture is key for healthy growth and abundant flowering.

During the peak of summer, when temperatures hover around 85°F, water deeply about once a week, providing roughly an inch of water. Use the finger test to check soil moisture: if the top two inches of soil feel dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can help prevent powdery mildew in our low-humidity environment.

Signs of underwatering include wilting leaves and stunted growth. Overwatering can lead to root rot, indicated by yellowing leaves and a mushy stem. Mulching around your borage plants with a layer of organic matter, like straw or wood chips, will help retain soil moisture and regulate soil temperature in our intense sun.

You can expect your first harvest of borage flowers and leaves from early July through late September, about 55 days after sowing. Harvest the star-shaped blue flowers when they are fully open for the best flavor and visual appeal. The young leaves are also edible and have a refreshing cucumber taste.

To harvest, gently snip off the flowers or leaves with scissors or pruning shears. Avoid pulling or tearing, which can damage the plant. Regular harvesting encourages continued production throughout the season.

As the first frost approaches in mid-September, harvest any remaining flowers and leaves. You can dry the flowers for later use or add the leaves to compost. Allowing some flowers to go to seed will ensure you have a volunteer crop next year, though be mindful of its self-seeding tendencies.

Here are some common problems you might encounter with borage in the Mountain West:

Self-Seeding Aggressively

• What it looks like: Borage seedlings popping up everywhere in your garden, even in unwanted areas.
• What causes it: Borage readily self-seeds, and our long sunny days help the seeds mature quickly.
• How to fix/prevent it: Deadhead flowers before they go to seed to prevent unwanted seedlings. If you don't mind volunteers, simply thin them out as needed.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems. Leaves curl, yellow, and die.
• What causes it: Fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. Even in our dry climate, powdery mildew can develop with evening condensation.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) can also be effective.

Can Become Leggy

• What it looks like: Tall, spindly plants with few leaves at the bottom.
• What causes it: Insufficient sunlight. Even though our sun is intense, borage can still get leggy if it doesn't receive enough direct light, especially later in the season as the sun angle changes.
• How to fix/prevent it: Ensure borage is planted in a location that receives at least 6 hours of direct sunlight per day. Prune back leggy stems to encourage bushier growth.

Mountain West Specific Challenges: Our moderate-at-altitude summer heat and low humidity generally favor borage, but be mindful of providing consistent moisture, especially during dry spells. The intense UV radiation can sometimes scorch leaves, so providing some afternoon shade can be beneficial.

Borage makes excellent companion plants for several vegetables in the Mountain West garden. It attracts pollinators that are beneficial for tomatoes, squash, cucumbers, and strawberries. Specifically, borage is said to deter tomato hornworms and squash bugs.

Avoid planting borage near fennel. Fennel inhibits the growth of many plants, including borage.