Bouteloua, Boutelou: Planting, Cultivation, Care

Description and botany

Bouteloua is a botanical genus belonging to the Poaceae family, formerly known as grasses. Native to the American continent, it can be found everywhere except in the extreme northwest and southeast. This botanical genus, which includes around forty annual or perennial varieties, is mainly used in gardens in two forms, Bouteloua curtipendula and Bouteloua gracilis (Blue Grama). An excellent forage plant, present in the arid and dry prairies of the ‘Great Plains’ that shaped the American landscape and remain a symbol today, this grass was named after two Spanish brothers, professional botanists, Claudio and Esteban Boutelou. Capable of growing in harsh conditions, Blue Grama thrives spontaneously in well-drained soils, even dry and calcareous ones, and in sunny exposures, possibly in partial shade. It is therefore no surprise to find it abundantly in the wild on rocky slopes, arid plains, and all open spaces from Canada to Argentina. This ability to withstand prolonged drought, combined with excellent hardiness, around -25°C to -30°C, makes it a grass of choice for our gardens, increasingly affected by long and severe heatwaves in summer. It will be more discreet in fresh soil and partial shade, and may even be overtaken by plants better suited to very wet conditions.

The Bouteloua forms a rather low clump of foliage, rather stiff and narrow, mostly growing from the base, and slightly pubescent. Grey-green, it displays more bluish hues if the soil is well-drained and the exposure sunny. Later in the season, it gradually takes on purplish, bronze-purple, and reddish-orange shades that are very decorative, before turning to parchment-like tan. Semi-evergreen in mild climates, it may go dormant and become deciduous in colder climates.

Bouteloua gracilis (left and top close-up of the inflorescence), and bottom right Bouteloua hirsuta

The flowering of Bouteloua is actually a spike formation; it usually begins around June and can last until September if the plant benefits from some moisture. It develops culms, whose height varies depending on growing conditions and species: Bouteloua curtipendula can reach nearly 90 cm, while Bouteloua gracilis rarely exceeds 40 cm. The inflorescences are compound. They are unilateral clusters of spikes, each containing numerous spikelets. They are thus borne almost exclusively on one side of the stem, at the top of an aphyllous peduncle, placed in line with the stem. The spikelets arranged this way resemble small combs or translucent brushes, silvery-pink to purple-violet, turning straw-yellow as they mature. The spike formation of Bouteloua has similarities with that of oats, which is likely what earned Bouteloua curtipendula its English name ‘side-oats grama’. The inflorescences develop vertically and then, gracefully arching, they form a light and airy cloud, like little accents floating magically in the air above the foliage. In Bouteloua gracilis, the spikes curl up characteristically at the end of flowering.

Requiring very limited maintenance (a cut back to the ground in early spring is sufficient), easily propagated by division or sowing, undemanding and hardy, this grass finds its place equally well in a flower border as inserted into a dry rockery, a scree garden, or a more contemporary space. Planted en masse, it can also substitute for a lawn, even in poor and very dry soils. Also disease-free, this grass with many qualities deserves to be discovered or rediscovered by gardeners facing increasingly unpredictable weather conditions each year.

The different species and varieties

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Planting and sowing Bouteloua

Where to plant?

Given its American origins, we know that Bouteloua grows in all types of soil, even poor and chalky, as long as it is sufficiently drained. A poor and stony terrain poses no problem for it, nor does a slope with often parched soil. Winter drainage is an important factor for the plant’s longevity, but a minimum of coolness in summer allows it to extend its flowering period, sometimes until September.

A bright, sunny, or even warm exposure is beneficial. Here, it develops more beautiful colours (its foliage tends towards blue and autumn hues are more pronounced) and its habit is more regular. It will tolerate growing in partial shade and in cool soil, but it loses some of its appeal and may eventually be outcompeted by other plants better suited to these conditions.

Like many grasses, you can plant it in a flowering border, in a naturalistic meadow, a more contemporary-style garden, on a slope, in a scree garden or a well-exposed rockery. Its grace can only enhance your composition.

Bouteloua gracilis

When to plant?

Although hardy down to around -25°C, Bouteloua is a warm-climate grass. To encourage establishment, planting in autumn (between September and November) is recommended in regions with mild winters, but wait until spring if your winters are harsh and wet.

How to plant and sow?

Planting Bouteloua

1. Soak the bucket in water to saturate the root ball.
2. Meanwhile, dig a hole two to three times the size of the root ball if possible.
3. In heavy, wet or poorly drained soil, lighten it with a not-too-rich compost and a draining material (pumice, gravel, river sand, clay pebbles…) mixed with the excavated soil.
4. Remove the root ball from its bucket and place it in the centre of the hole, positioning it so that the top of the root ball is level with the ground once the soil is firmed.
5. Water thoroughly to soak the substrate and ensure contact with the root ball soil.
6. Mulch to a depth of 2 or 3 cm, with a material of your choice (choose a mineral or organic mulch depending on your style or constraints).

–> In the following weeks and months, ensure you water your young plants if rainfall is lacking. Once established, your Bouteloua will tolerate drought very well.

Sowing Bouteloua

Sowing is best done in early spring, either in buckets for transplanting in autumn or the following spring depending on your climate, or by direct sowing, broadcast.

In buckets,

1. Sow the seeds spaced out on the surface of the compost, then cover lightly with sieved compost or, better still, with perlite or vermiculite.
2. Soak your container in water to slowly saturate all the compost by capillary action.
3. Place in a warm, airy and bright spot, keeping moist but not waterlogged.
4. Thin out as needed as germination occurs, and when the plants have developed a few true leaves, transplant them into individual pots filled with standard, well-drained compost, then plant them out in autumn or spring depending on your region.

Direct sowing,

1. Weed, clear and rake the area to be sown.
2. Sow your seeds evenly and fairly spaced. Cover with a thin layer of compost and water with a fine spray.
3. Keep moist until germination, then support growth during the first year.

–> Thereafter, Bouteloua tolerates drought well.

Maintaining Bouteloua

Maintaining Bouteloua is extremely easy and not time-consuming.

• Ensure the base of young plants remains cool after planting, as this promotes good root development – just remember it’s better to water thoroughly once a week rather than lightly every day.
• In early spring, simply cut back any remaining leaves close to the clump.

Bouteloua gracilis

Propagate

Bouteloua propagates easily. Dividing the clump is the quickest and most practical way to obtain a well-established young plant. However, it is also possible and easy to sow this grass (see above) if you wish to obtain more at a lower cost, for example when using it as a lawn substitute.

Dividing a Bouteloua clump

Preferably carry this out in early spring under cold and humid climate. Elsewhere, you can also apply this technique in autumn.

1. Using a spade, circle your young plant of Bouteloua, about 10 cm beyond the clump’s perimeter.
2. Lift the clump from the soil, taking care to keep as much earth around the roots as possible.
3. With a sharp tool (such as a sharpened spade), slice the rootball into 2 or more sections, ensuring each has at least one healthy leaf cluster and roots.
4. Replant immediately in the desired location or in buckets.
5. Water and mulch.

Pairing Bouteloua in the Garden

The Bouteloua, highly adaptable, lends itself to multiple uses, from the most romantic to the most contemporary.

• In a flowering border, enjoy its delicate and airy flowering in summer and early autumn alongside roses, and medium to tall perennials such as Rudbeckia, Echinacea, Asters, Solidago or other ornamental grasses like Andropogon gerardii.
• In a naturalistic meadow, it works wonders with artemisias like Artemisia lactiflora ‘Guizhou’, towering Silphium perfoliatum, Monardas, Eupatoriums, or warm-toned Heleniums.

Bouteloua gracilis, Silphium perfoliatum, Monardas and Heleniums.

• On a slope, pair it with undemanding plants that, like it, tolerate dry conditions. Ceanothus fit this category, flowering in blue, white, or pink from March to October depending on the species. Roses, lavenders, and St. John’s wort also make good companions. For perennials, consider yarrows, hardy geraniums, Nepeta, and perennial sages.
• In a sunny rockery, it adds lovely accents among sedums, festucas, artemisias, pinks, and santolinas. A few dwarf conifers also create beautiful contrasts in form and colour. Small gaps between rocks can host early-flowering bulbs (Chionodoxa, Crocus, Snowdrops, Daffodils, and Botanical Tulips) or autumn-flowering ones (Colchicums, Sternbergia lutea).
• In a scree garden, plant clumps irregularly and enhance the natural effect with other grasses like Stipa tenuifolia, blue fescue, Andropogon, or upright panic grass. For flowering companions, fleabanes, asters, lavender, rockroses, or moss phlox thrive in similar conditions.
• In a Mediterranean border, it pairs beautifully with iconic plants like Provence or Italian cypresses, rockroses, olive trees, oleanders, lavenders, or strawberry trees.
• In a modern composition, mix it with Carex, golden-leaved (Carex ‘Everillo’) or variegated (Carex ‘Everest’), agapanthus, bamboos (some varieties stay neatly contained), birches with pristine bark, or Mahonias in cooler spots.

Mahonia, Agapanthus, Bouteloua gracilis, Fargesia murielae bamboo and Carex oshimensis ‘Everest’

→ Discover 7 more pairing ideas with Bouteloua in our advice guide!