Landscape Journal - Creating Spring Garden Interest

This winter was a long one for many of us, which has made the onset of spring particularly exciting. In this month’s post, we suggest ways to add interest to the garden when warm season grasses are still dormant or just emerging. Spring flowering bulbs, sedges, and cool season grasses can fill the gap until soil and air temperatures warm and the garden gets going.

Spring Flowering Bulbs

Last year, we decided to plant hundreds of bulbs around our landscape. We concentrated them in areas with large grass plantings that cover the ground in summer through early winter. Those spots can feel bare when the grasses are cut back. The earliest flowering bulbs will often peek out of the ground before the grasses are cut back. These early bulbs fill in quickly and provide a link in the succession of blooms and interest across the season.

We worked with Brent Heath of Brent & Becky’s Bulbs in Gloucester, Virginia. He loves to pair grasses and sedges with bulbs, and he sent us a curated selection. We received the shipment in November and planted them mid-December. Most spring-flowering bulbs are best planted in fall, but here in the Southeast we can plant quite late.

Crocus in mid-February in North Carolina.
Crocus in mid-February in North Carolina.

In the South, Daffodils (Narcissus) are reliable performers and look fantastic in masses. Early bloomers like ‘Surfside’, ‘Las Vegas’, and ‘Marieke’ are favorites. Crocus, with their grasslike foliage, mingle well with sedges and other cool-season growers. Crocus tommasinianus is a small, yet powerful addition. It naturalizes and helps crowd out early weeds. Other naturalizers like Spanish Bluebells (Hyacinthoides hispanica) and Star Flower (Ipheion uniflorum) also form colonies that fill gaps.

Although Snowdrops (Galanthus) and Winter Aconite (Eranthis) don’t do as well for us here, they are strong and reliable in cooler climates. Corydalis species and cultivars are great choices, too. You can find varieties that are blue, along with a range from yellow to red. They give an early pop of color, and their foliage helps cover bare ground and suppress weeds. Depending on where you’re located, different bulbs may be more suitable. The foliage of later-blooming varieties may persist into spring, but resist cutting them back. Other forbs and grasses usually push through the spent foliage and cover it.

Galanthus in February through March.
Our garden coordinator Kata Kreß Wallace shared several images from Europe with us. This garden in Austria turns into a lush prairie in summer but is filled with Galanthus in February through March.

In this image from Austria, Corydalis transsilvainca mingles with Eranthis and foliage of Iris and Ipheion.
In this image from Austria, Corydalis transsilvainca mingles with Eranthis and foliage of Iris and Ipheion.
Inflorescences of Allium hovering above emerging grasses
Jumping ahead a bit—when spring slides into early summer, the rounded inflorescences of Allium look fantastic hovering above emerging grasses. This planting at the Chicago Botanic Garden melds them beautifully.

Sedges and Cool Season Grasses

In addition to bulbs, sedges (Carex) and cool season grasses bridge the spring gap. Their photosynthetic processes are most efficient at cooler temperatures. They break domancy and grow early in the spring before the full heat of summer hits. Here in the South, many emerge in March, and by mid-to-late April are full and lush.

Beyond Blue Fescue adds a bright pop of color.
Beyond Blue Fescue adds a bright pop of color.

Colorful cool season grasses like Blue Fescue (Festuca glauca Beyond Blue and ‘Elijah Blue’) pop with fresh and appealing foliage. We also love the sweeping, fine texture of Nassella tenuissima (Mexican Feather Grass). If you’re in a climate with lower heat and humidity than we have, you have even more options for cool season grasses: Helictotrichon sempervirens ‘Sapphire’ (Blue Oat Grass), Arrhenatherum elatius subsp. bulbosum ‘Variegatum’ (Striped Tuber Oat Grass) and Deschampsia (Hair Grasses).

We really love sedges for spring interest. Most people use Carex for its foliage and functional qualities, but the blooms are worth noticing. The flowers differ from grasses and offer unique, intricate structures. Carex divulsa (Grassland Sedge) shows lush growth and charming blooms early for us in the Southeast. By late April, it’s already grabbing attention.

By early April, Carex divulsa is lush and green with emerging inflorescences.
By early April, Carex divulsa is lush and green with emerging inflorescences.

Carex grayi (Gray’s Sedge) is a favorite with our garden team. The blooms and seedheads of this North American native are remarkable. We have Gray’s Sedge planted in one of the bioswales near a greenhouse—what an eyecatcher! Carex rosea (Rosy Sedge) has some of the cutest blooms of all the sedges we grow. The flowering stems extend out over the foliage, which makes them stand out. It can take a season or two after planting to see and enjoy a full set of blooms, but it is worth the wait!

The blooms of Carex grayi are showy and bright by early May.
Carex grayi is showy and bright by early May.

Carex bicknellii (Bicknell’s Sedge) is another wonderful native Carex, and is one of our “all-arounders.” It does well in dry to moist soils and isn’t fussy, probably because it lives in prairies as well as in rocky areas. It has small, intricate flowerheads that are distinctive among the sedges we grow.

Grasses have many advantages, but including warm season varieties means there’s a slow time. In garden areas with warm season grasses, layer with spring-flowering bulbs, sedges, and cool season grasses to give your spring garden a boost.

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