Hummingbird sage (Salvia spathacea) is a popular ornamental plant native to California and Oregon. This aromatic evergreen perennial is prized for its attractive foliage and its ability to attract hummingbirds and other pollinators to the garden. However, some gardeners are hesitant to grow hummingbird sage because of concerns that it may spread aggressively and become weedy. This article will examine the growth habits and spreading potential of hummingbird sage to help you determine if it is an appropriate choice for your landscape.
About Hummingbird Sage
Hummingbird sage is a member of the mint family Lamiaceae. It grows 1-3 feet tall and wide, with a mounded form. The leaves are basal, meaning they emerge near the base of the plant. The foliage is aromatic and covered in tiny hairs. The leaves are oblong to spoon-shaped and range in color from gray-green to bright green.
In late spring through summer, hummingbird sage produces whorls of small tubular flowers in shades of pink, purple, or white. These flowers attract hummingbirds, butterflies, and bees. After the flowers fade, the plant forms small brown seed pods.
Hummingbird sage thrives in full sun and well-drained soil. It is drought tolerant once established. This sage can handle a variety of soil types and does well in coastal gardens. It is hardy to USDA zones 8-11 on the West Coast.
Growth Habits
Hummingbird sage grows at a moderate rate. Mature plants may reach 2-3 feet tall and wide. Growth occurs from a woody base with new leaves emerging each spring. Flowering stems emerge from the basal foliage.
This sage has a bushy, mounded form. It does not grow overly large or tall. Proper pruning can help maintain its compact shape.
Spreading Potential
Hummingbird sage spreads slowly via rhizomes (underground stems). However, it does not spread aggressively or become weedy like some other mint family plants.
With adequate space, hummingbird sage may spread 1-2 feet over a few years. But it is not prone to rampant spreading and rarely becomes a nuisance.
Keeping the plant pruned and contained within garden beds will prevent unwanted spread. It’s also easy to dig up and divide congested plants or remove unwanted growth.
Here is a table comparing the spreading potential of hummingbird sage to other common ornamental plants:
| Plant | Spreading Potential |
|---|---|
| Hummingbird sage | Slow, moderate, easily managed |
| English ivy | Rapid, aggressive, invasive |
| Hostas | Slow, easily managed |
| Snow-in-summer | Moderate, can spread rapidly in ideal conditions |
| Purple coneflower | Moderate, self-seeds freely |
As the table illustrates, hummingbird sage has less spreading potential than notoriously invasive plants like English ivy. With proper siting and occasional maintenance, spreading can be prevented altogether.
Containing and Managing Spread
Here are some tips to prevent hummingbird sage from spreading beyond its intended bounds in your landscape:
Provide Adequate Space
Allow enough room for hummingbird sage to grow to its mature size without being crowded. Avoid planting it too close to walkways or other plants.
Use Barriers
Installing a barrier around the perimeter can prevent rhizomes from spreading. Options include:
– Plastic or metal landscape edging
– Buried patio blocks, bricks, or stones
– Gravel or mulch border
Divide Regularly
Every 2-3 years, dig up overgrown plants. Divide them and re-plant divisions to rejuvenate growth. Discard excess divisions.
Prune Flowering Stems
Pruning back flower stems after blooming prevents self-seeding. Remove spent flowers before seed pods form.
Monitor and Remove Runners
Check periodically for rhizomes spreading beyond the desired boundaries. Carefully dig up and remove any unwanted growth.
Grow in Containers
Growing hummingbird sage in pots, planters, or window boxes eliminates the possibility of spreading. Use a quality potting mix and provide drainage holes.
Companion Plants for Hummingbird Sage
Here are some great options for plants to pair with hummingbird sage:
Perennials
– Penstemon
– Salvia
– Asters
– Sages
– Agastache
– Verbena
– Catmint
Grasses
– Blue oat grass
– Purple fountain grass
– Maiden grass
– Feather reed grass
Shrubs
– Manzanita
– Ceanothus
– Buddleia
– Escallonia
– Wild lilac
Choose companion plants with similar growth habits and soil/exposure preferences. Aim for a cohesive look and use plants that will attract and benefit pollinators. Foliage color, height, and texture should complement hummingbird sage’s silvery-green leaves and bushy form.
Uses for Hummingbird Sage in the Landscape
Here are some great ways to utilize hummingbird sage in your garden:
Pollinator Gardens
With its nectar-rich blooms that attract hummingbirds and butterflies, hummingbird sage is an ideal choice for pollinator-friendly plantings. Combine it with other sages, salvias, agastache, monarda, penstemon, and native wildflowers.
Borders and Beds
The compact, mounded form of hummingbird sage works well along borders and garden beds. Place it at the front or middle of beds clustered with other perennials and ornamental grasses.
Slope Groundcover
Hummingbird sage’s dense foliage and spreading habit make it useful as an erosion control groundcover on dry slopes and banks. Space plants 1-2 feet apart.
Container Gardens
The petite size and bushy shape of hummingbird sage is perfect for patio pots and window boxes. Combine with annuals, herbs, and other perennials in a pollinator-friendly container design. Provide well-drained soil and do not allow pots to freeze in winter.
Tips for Growing Hummingbird Sage
Here are some top tips for successfully growing this California native plant:
Sun and Soil
– Provide at least 6 hours of full sun
– Well-drained soil is essential
– Avoid wet, poorly drained sites
– Tolerates a range of soil types and amended garden soils
– Does not tolerate overly dense, clay soils
Planting
– Space plants 2-3 feet apart
– Set root ball at same level it was growing in the nursery pot
– Backfill with native soil
– Water thoroughly after planting
Watering
– Drought tolerant once established
– Water weekly the first season after planting
– Occasional deep soakings are better than frequent light watering
– Reduce water in winter
– Allow soil to dry between waterings
Fertilizer
– Apply balanced organic fertilizer at planting
– Fertilize established plants in early spring
– Avoid high-nitrogen fertilizers that promote leggy growth
Pruning
– Prune lightly in spring to shape and improve density
– Remove spent flower stems after blooming
– Cut back any leggy growth or dieback as needed
– Avoid shearing or heavy pruning
Troubleshooting Problems
Hummingbird sage is relatively trouble-free, but may experience a few common issues:
Powdery Mildew
This fungal disease appears as a white powdery coating on leaves, causing leaf drop. It often occurs in cool, humid conditions. Improve air circulation and avoid wetting foliage. Remove affected growth promptly.
Root Rot
Overwatering can lead to root rot. Allow soil to dry between waterings and ensure adequate drainage. Avoid planting in wet sites.
Aphids
These small sap-sucking insects can build up on new growth but typically don’t cause major damage. Knock off with a strong spray of water or use horticultural oil/insecticidal soap sprays as needed.
Snails and Slugs
These pests chew holes in foliage and can be a problem in moist conditions. Reduce habitat via debris removal. Trap snails with beer in shallow containers buried to the rim. Use iron phosphate bait as needed.
Conclusion
Hummingbird sage is valued for its ornamental merits and ability to attract pollinators. When sited properly and managed with occasional pruning and division, it has a low potential to spread out of control. This makes it a great choice for gardens in California, Oregon, and other mild climates. Pair hummingbird sage with penstemon, agastache, salvias, and other West Coast native plants to create a lively landscape that supports bees, butterflies, and hummingbirds.
