Borage in Zone 3B — Mountain West

Borage is a fantastic addition to any Mountain West garden. The star-shaped blue flowers are beautiful and attract pollinators, and the cucumber-flavored leaves and flowers add a unique twist to salads and drinks. Plus, it's incredibly satisfying to grow something so useful and eye-catching in our short season.

Our high altitude, intense sun, and short growing season can be challenging, but borage is surprisingly well-suited to our climate. With a 108-day growing season, you can easily fit in a crop of borage, especially if you direct sow.

If you're starting borage indoors, transplant seedlings outdoors mid-May through early June, after the risk of hard frost has passed. Before planting, 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 of our Mountain climate.

Space your borage plants 12-18 inches apart to give them room to grow. Even in late spring, keep an eye on the forecast for unexpected cold snaps or late-season hail. Be prepared to cover your young plants if needed.

Direct sowing is the preferred method for borage in our region. Wait until late May through early July, when the soil has warmed up a bit. Borage seeds germinate best in soil temperatures around 60-70°F.

Prepare your planting bed by loosening the soil and amending with compost if needed. Our alkaline soil can benefit from the added organic matter. Sow seeds about ½ inch deep and 12-18 inches apart. Keep the soil consistently moist until seedlings emerge. Borage is easy to direct sow and readily self-seeds, so be prepared for volunteers next year!

Borage needs moderate watering, especially when young and establishing its root system. While it's a fairly easy-going plant, it's not particularly drought-tolerant, so don't let it dry out completely.

In our dry Mountain West climate, a good rule of thumb is to water deeply once or twice a week, providing about 1 inch of water each time. Use the "finger test" to check soil moisture – if the top 2 inches of soil feel dry, it's time to water. Water at the base of the plant to avoid wetting the leaves, 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 generally unhealthy appearance. A light layer of mulch, like straw or wood chips, can help retain moisture in the soil and regulate soil temperature, which is beneficial in our climate.

You can expect your first borage harvest from mid-July through mid-September, about 55 days after planting. The star-shaped blue flowers are ready to harvest when they are fully open. Young leaves are also edible and have a refreshing cucumber flavor.

To harvest, gently snip off the flowers or leaves with scissors or your fingers. Be careful not to damage the main stem. Regular harvesting encourages continued production of both flowers and leaves.

As the first frost approaches in early September, you can harvest all remaining flowers and leaves. Consider letting a few plants go to seed to ensure a supply of volunteers for the following year.

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

Self-Seeding Aggressively

• What it looks like: Numerous borage seedlings popping up in unwanted areas of your garden.
• 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, or pull up unwanted seedlings as they emerge. Consider growing borage in containers to limit its spread.

Powdery Mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die.
• What causes it: Various fungi thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it. While our humidity is low, cool nights can create localized humid microclimates.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning if necessary. Remove affected leaves. Neem oil or potassium bicarbonate sprays can help. A milk spray (1 part milk to 9 parts water) is surprisingly effective.

Can Become Leggy

• What it looks like: Tall, spindly plants with few leaves, often flopping over.
• What causes it: Insufficient sunlight or overcrowding can cause borage to stretch towards the light, becoming leggy.
• How to fix/prevent it: Ensure borage receives at least 6 hours of direct sunlight per day. Space plants appropriately and provide support if needed. Pruning can also encourage bushier growth.

Mountain West Specific Challenges: The intense sun at our high altitude can sometimes scorch borage leaves, especially if plants are not adequately watered. While our low humidity generally reduces disease pressure, powdery mildew can still be a problem, particularly during periods of cool nights and warm days. The dry rainfall pattern means you'll need to be diligent about watering, especially during dry spells.

Borage makes a great companion plant for several vegetables in your Mountain West garden. It attracts pollinators, which benefits tomatoes, squash, strawberries, and cucumbers. Borage is also said to deter pests like tomato hornworms.

There are no known bad companions for borage, so feel free to plant it wherever you need a pollinator attractant or pest deterrent. Just be mindful of its tendency to self-seed and spread.