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May Knight Salvia

Salvia x sylvestris

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May Knight Salvia. Purple-blue flowers spikes

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During those hot summer days, you should consider adding some cool tones to your garden. The deep, creamy blue flowers of the May Night salvia (Salvia x sylvestris ‘Mainacht’) provides some visual appeal throughout your yard. If you are tired of those harsh reds and oranges in the summer, you should supplement your space with the May Night salvia’s cool blue hues.

Plant Attributes

For those who want to add cooler colors to their landscape, the May Night salvia is just the plant for you. In the late spring season, the blue flowers start to bloom. After the first flush of blooms, you should trim them for more abundant flowers throughout spring and summer. The bluish-green stems are full of these violet-purple flowers, and they last until the fall. These deep colors make a great focal point as they draw your eye to the plant.

This salvia plant is one of the most popular flowers for butterflies. You will see these creatures as they head to your garden to enjoy the sweet nectar. These visitors add a touch of color and motion to an established landscape.

With its upright and compact form, this plant works well in any space. The bold shades of blue and purple are perfectly contrasted against other bright hues.

Landscape Use

If you want a filler plant for those mass spaces or need something for a home garden, the May Night salvia is an exceptional choice. The bluish-gray foliage has an aromatic scent, and it provides an attractive accent for those long summer days. This salvia maintains its compact form year-round.

For a striking look, these plants do well when used as a mass planting. When grouped together, you can enjoy these rich bluish flower spikes. They can even be used as a low-edging plant for your borders to create a walkway. If you brush against the foliage, you will be treated to a floral fragrance that stays in the air.

When creating a low hedge, plant them at least two feet apart on center. Mass plantings will work best if you use a series of zigzagging rows. A fresh layer of mulch helps to protect the roots and keep away those weeds.

Taller perennials and short shrubs make an excellent backdrop for these brilliant blue plants. With its textured look, you can enjoy this salvia throughout the year. As the butterflies visit, you will feel relaxed in your own personal retreat.

On those patios and porches, the May Night salvia makes an excellent filler for container gardens. You can even add several smaller pots together for a bold look to your outdoor spaces. Don’t forget about your indoor areas. The May Night salvia blooms are perfect in a fresh floral arrangement.

Planting & Care

The May Night salvia needs full sun exposure with six hours of direct sunlight. While the May Night does not prefer a particular soil pH or type, it does require well-draining soil. Mulch should be used to keep those roots cool and moist. It can also help to reduce your time between watering.

New May Night plants need a moderate amount of water. Once the roots have been established, this plant is considered a low water user. You might want to add an automatic drip irrigation system for these plants. The May Night salvia needs to be watered regularly, especially if you live in a climate with hot, dry weather.

The May Night salvia thrives in USDA hardiness zones 3 to 9. It makes an ideal home for hummingbirds, butterflies, and other insects. You won’t have to worry about deer since they seem to leave this salvia variety alone.

If you want to increase the blooms, you should cut back the salvia after the flowers’ first flush. With a light prune, it can help rejuvenate the foliage and increase the summer blooming time.

Additional Information

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May Knight Salvia


For purple-blue flowers throughout the summer, you need to choose the May Night salvia. This perennial is durable, and it provides color for your outdoor spaces. In the late spring, you will notice the impressive flower spikes. When deadheaded, it will rebloom in late summer. You can add some blue hues to your landscape with this spectacular salvia variety.

At Arbor Valley Nursery, we carry a large selection of garden products, including the May Night salvia. If you have any questions about this variety or other products, please reach out to us. For more information, make sure to fill out the contact form.

Plant Features

  • Watering Needs: regularly – weekly, or more often in extreme heat or containers.
  • Botanical Pronunciation: SAL-vee-uh sil-VES-tris
  • Plant type: Perennial
  • Deciduous/evergreen: Herbaceous
  • Growth rate: Fast
  • Average landscape size: Reaches 18 to 24 in. tall
  • Special features: Attracts butterflies, Hummingbirds, compact form, easy care
  • Dramatic Foliage: grey-green
  • Foliage color: Green shades
  • Blooms: Early summer through midsummer
  • Flower color: Purple-blue shades
  • Flower attributes: Showy Flowers
  • Garden style: Cottage
  • Design Ideas: excellent for mixed borders, flower beds, and patio containers.
  • Companion Plants: Blanket Flower (Gaillardia); Black-Eyed Susan (Rudbeckia); Blue Fescue (Festuca); Shasta Daisy (Chrysanthemum); Coneflower (Echinacea)

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