Borage in Zone 9B — Desert Southwest

Borage is a fantastic addition to any Desert Southwest garden. Its beautiful blue, star-shaped flowers are edible and attract pollinators, and the leaves have a refreshing cucumber-like flavor that's perfect in salads or drinks. Plus, borage is incredibly rewarding to grow, offering a vibrant splash of color and flavor in our arid landscape.

Sure, our region presents challenges with extreme heat and alkaline soil, but borage is surprisingly adaptable. With our long 313-day growing season and careful planning, you can enjoy a bountiful harvest of borage from spring all the way through fall.

If you want a head start, you can transplant borage outdoors in late January through mid-February. Remember to harden off your seedlings for about a week before transplanting. Gradually expose them to the outdoor elements so they aren't shocked by the intensity of our Desert Southwest sun.

Space your borage plants 12-18 inches apart to allow for good air circulation. Keep an eye on the weather forecast, as we can still get some cold snaps that time of year. If a frost is predicted, protect your young transplants with frost cloth.

Direct sowing is the easiest and most common way to grow borage, and it thrives when sown directly into the ground here in the Desert Southwest. You can direct sow borage seeds from early February through early October. This gives you two distinct planting windows to take advantage of our mild winters and long growing season.

Prepare your soil by loosening it and adding some compost to improve drainage and fertility. Borage prefers a soil temperature of around 60-70°F for optimal germination. Sow seeds about 1/2 inch deep and 12-18 inches apart. Keep the soil consistently moist until the seedlings emerge. Borage is known to self-seed readily, so be prepared for volunteers in the following seasons!

Borage needs moderate watering to thrive in our arid Desert Southwest climate. While it's a fairly easy-going plant, consistent moisture is key, especially during our hot summers. Remember, it isn't drought tolerant!

During the spring and fall, when temperatures are milder, water your borage plants about 1 inch per week. In the extreme heat of summer, increase watering to 2 inches per week, or more if the leaves start to wilt. Use the finger test to check soil moisture: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water.

Water at the base of the plant to avoid wetting the foliage, which can increase the risk of powdery mildew in our warm climate. Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to root rot, so watch out for yellowing leaves. A layer of organic mulch around your borage plants will help retain moisture and keep the soil cool.

You can expect your first borage harvest about 55 days after planting, which means you'll be harvesting from early April through late December in our Zone 9B Desert Southwest garden. The best time to harvest borage flowers is when they are fully open and vibrant blue.

Pinch off the flowers at the base of the stem, being careful not to damage the plant. Young leaves can be harvested throughout the season as needed. Simply snip off a few leaves at a time, leaving the rest of the plant to continue growing.

To encourage continued production, deadhead spent flowers regularly. As our first frost approaches in mid- December, you can let some of the last flowers go to seed, ensuring a new crop of borage next spring.

Here are the most common problems you might encounter with borage in the Desert Southwest:

Self-seeding aggressively

• What it looks like: Borage seedlings popping up everywhere in your garden, even where you didn't plant them.
• What causes it: Borage is a prolific self-seeder, and the seeds can remain viable in the soil for several years. Our mild winters allow for year-round germination.
• How to fix/prevent it: Deadhead spent flowers before they go to seed. Remove unwanted seedlings as soon as you see them. Consider growing borage in containers to limit its spread.

Powdery mildew

• What it looks like: White or grayish powdery coating on leaves, stems. 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 (unlike most fungi). Our monsoon season can create brief periods of higher humidity, making borage susceptible.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning if needed. Remove affected leaves promptly. Neem oil or potassium bicarbonate sprays can help. Milk spray (1 part milk to 9 parts water) is surprisingly effective.

Can become leggy

• What it looks like: Long, spindly stems with few leaves, causing the plant to flop over.
• What causes it: Insufficient sunlight, especially during the shorter days of spring and fall.
• How to fix/prevent it: Plant borage in a location that receives at least 6 hours of sunlight per day. Prune leggy stems to encourage bushier growth.

Desert Southwest Specific Challenges: Our extreme heat can stress borage plants, making them more susceptible to powdery mildew. The arid humidity can also lead to rapid drying of the soil, requiring more frequent watering. While monsoon moisture is welcome, it can also create favorable conditions for fungal diseases.

Borage makes excellent companion plant, and it does particularly well with certain plants in our Desert Southwest gardens. Plant borage near tomatoes to deter tomato hornworms and attract pollinators that will increase fruit set. Squash benefits from borage as it attracts beneficial insects that prey on squash bugs and vine borers. Strawberries love borage because it attracts pollinators and may help deter pests. Cucumbers also enjoy the company of borage, as it helps to attract pollinators and improve fruit production. Avoid planting borage near fennel, as it can inhibit its growth.