<em>Dasylirion</em>: how to plant, to grow and care for

Description and botany

Dasylirion belongs to family Asparagaceae and originates from rocky and semi-desert areas of Mexico and the south-west United States (notably Texas). Genus comprises eighteen different species. These are xerophytic bushes, that is capable of withstanding severe water deficits. Dasylirions are therefore perfectly suited to cultivation in warm, dry Mediterranean climate.

Habit of bush in its youth is limited to a kind of large radiant ball made up of thin leaves that starts almost at ground level. With age, the ball is borne on a thin trunk which gradually grows to finally bend, even lie down, giving the plant a particularly picturesque habit. As you can imagine, dasylirions sold with a well-developed trunk are already fairly old, which often explains a prohibitively high price.

It is a rhizomatous plant whose root system is fragile and does not appreciate being disturbed. It is therefore important to choose planting spot carefully because once planted it will be very difficult to move without risk. 

Foliage is evergreen. Leaves are numerous and relatively thin, forming a rosette at top of the trunk. They are fibrous, glabrous and armed with acute, recurved thorns on the margins. Sometimes a wax covers the leaves to reduce evapotranspiration.

Flowering may appear only after around ten years and if all conditions are met: mature plants, warm temperatures and some humidity. Dasylirions therefore do not necessarily flower every year. Inflorescence unfolds into narrow panicles of small cream-white flowers on a woody flower stalk over 3 metres high, sometimes much higher. Depending on species, upper flowers on the stalk may have tepals of dark red, yellow or green. Male and female flowers are borne on separate individuals: the plant is dioecious. However, no need to worry, the plant does not perish after flowering as is the case with agaves, for example.

Dasylirion – botanical illustration

Fruit resulting from fertilization of the flower is a dry indehiscent fruit and a three-winged capsule. Seed is brown.

Growth is faster in ground and much slower in a pot: allow 20 cm to 30 cm per year in ground for only a few centimetres in a pot. Longevity can exceed a century if cultural conditions suit it.

Here is a short presentation of the most commonly encountered species:

Dasylirion acrotrichum (hardy down to -16 °C): bluish foliage but bordered by numerous hooks.

Dasylirion berlandieri or Berlandier’s Dasylirion (hardy down to -12 °C): yellow flowers and dense foliage with leaves up to 1.50 m long armed with sharp teeth. Trunk is thick and fairly short.

Dasylirion glaucophyllum (hardy down to -16 °C): yellow-green flowers, thin blue-grey leaves armed with almost transparent thorns.

Dasylirion longissimum (hardy down to -15 °C): dark red flowers, very thin and flexible leaves. Lightest and most elegant of the Dasylirions.

Dasylirion lucidum (hardy down to -12 °C): thin leaves and less thorny than other dasylirions. Several rosettes of leaves may develop on the trunk.

Dasylirion serratifolium (hardy down to -8 °C): white flowers, glaucous and fairly broad leaves.

Dasylirion texanum (hardy down to -18 °C): cream-coloured flowers, blue-grey leaves.

Dasylirion wheeleri (hardy down to -20 °C): cream-white flowers borne on a stalk reaching up to 6 metres, leaves broad and shorter than in other species, edged with orange thorns.

Dasylirion glaucophyllum : foliage and detail of flowering

Our favourite varieties

Dasylirion glaucophyllum - Sotol

Dasylirion glaucophyllum is striking thanks to its long, very stiff, glaucous leaves that form a giant sea-urchin-like ball borne on a short trunk. Plant reaches full size when it flowers, after several years, producing a huge flowering stem covered in small yellow flowers.

• Flowering time July to September
• Height at maturity 2 m

See the product sheet

Dasylirion longissimum - Sotol

Dasylirion longissimum grows to 2 m tall and forms a rosette of long, linear leaves creating a spherical habit borne on a short stipe. Plant takes its time to flower but, after 10 to 15 years, a huge flowering stem covered in yellow flowers shoots up from the rosette.

• Flowering time July to September
• Height at maturity 1,70 m

See the product sheet

Dasylirion wheeleri - Sotol

Dasylirion wheeleri is distinguished by its shorter, more bluish leaves than other species. It is also the most resistant in the group to cold, damp conditions. It too flowers after 10 to 15 years.

• Flowering time July to September
• Height at maturity 1,70 m

See the product sheet

Planting Dasylirion

Where to plant?

Dasylirions love sun and heat, without these they will eventually wither.

They need very well-drained soil to prevent stagnant water from rotting roots.

Planting in open ground should only be attempted in regions with mild climate: USDA hardiness zones 7b, 8a, 9a, 10a. Elsewhere, only pot cultivation can be considered.

Avoid high-traffic areas as plant leaves are spiny and can scratch. Also, leaf latex is toxic.

When to plant?

Planting should be done in spring or early summer, between April and July. Do not attempt planting in cold weather!

How to plant?

In open ground

• Re-wet the rootball by immersing the plant in water for a few minutes, drain then remove it from its pot
• Prepare a hole twice the volume of the rootball
• Keep the excavated soil and mix it with coarse sand, gravel or pumice to lighten it, especially if it is heavy
• Avoid placing a layer of gravel at the bottom of the hole to improve drainage as is sometimes suggested; this actually increases water pooling near the roots. Instead, add a few handfuls of potting compost to the bottom of the hole
• Place the rootball in the hole and fill with the excavated soil (mixed with sand and gravel)
• Firm the soil lightly around the base of the plant
• Give a good watering to reduce the risk of air pockets forming between the substrate and the roots
• A mineral mulch is a good idea. It will help retain moisture without excess, protect against frost, and remain aesthetically pleasing.

In a pot

• Choose a container large enough—at least three times the rootball—because, although the plant grows slowly, it will eventually reach a considerable size over time.
• Re-wet the rootball and remove the plant from its pot
• Use a free-draining substrate: 2/3 general-purpose potting compost and 1/3 coarse sand
• Consider placing a good layer of gravel at the bottom of the pot for drainage (this time it is acceptable because roots will not reach the bottom for some time. When they do, the plant will need repotting into a larger container).
• Place the Dasylirion in its new container and fill with the substrate
• Give a thorough watering and place pebbles around the base: they will be decorative and provide a mineral mulch that protects the plant from frost and excessive evapotranspiration.

→ Also read: Growing a Dasylirion in a pot

Dasylirion longissimum with its incredible flower spike !

Care and maintenance

Care

In very dry periods, water occasionally at the base but always sparingly. This will help the plant keep attractive foliage and grow faster.

In winter, you can protect your Dasylirion with a winter fleece if temperatures fall below -12 °C. On a terrace, wrap pot and plant.

Find out more in our care sheet : How to overwinter a Dasylirion? Our tips for protecting it from the cold.

Pruning

Dasylirion requires no pruning.

Pests and diseases

Dasylirion is not prone to pests. Its only issue may be root rot if soil is not sufficiently drained.

Multiplication

Propagation is, unfortunately, almost impossible for private individuals.

Producers propagate plants by sowing. But seeds are only produced if a male young plant and a female young plant are in close proximity and in flower at the same time.

As a last resort, one can try removing offsets at the base of the stipe. But the operation is delicate: the removed rosette must include a good portion of the rootball, and success is not guaranteed.

Pairing Dasylirion

In a bed of graphic, exotic and desert foliage

Dasylirion wheeleri will be magnificent on its own; accompanied by a tapetum of Delosperma ‘Wheels of Wonder Orange’ it will simply be stunning. It can be paired with a few agaves, including Agave americana, whose bluish tones inevitably recall Dasylirion foliage. A superb Aloe striatula will cut a fine figure beside our two companions with its very graphic habit but, above all, its flowering reminiscent of kniphofias — a radiant yellow-orange colour that contrasts with the bluish tones of other plants’ foliage while providing an echo for the Delospermas. Impressive Phormium tenax ‘Variegatum’ also flowers in yellow tones but offers foliage marginate with cream-white.

An example of an association in an exotic-desert bed: Dasylirion wheeleri, Delosperma ‘Wheels of Wonder Fire’ (or ‘Wheels of Wonder Orange’), Agave americana, Phormium tenax ‘Variegatum’

In a pot on a contemporary terrace

Dasylirion glaucophyllum is undoubtedly one of the most beautiful and will be particularly at ease in a pot on your terrace, alongside a dwarf palm with bluish foliage similar to Dasylirion: Chamaerops humilis ‘Compacta’. A large Agapanthus ‘White Heaven’ with white flowering and a very graphic habit, together with a pot of Kniphofia ‘Mango Popsicle’ featuring warm orange flowers, will complete the picture. Sober, elegant grey-blue pots in a colour that harmonises with the plants will look superb.

Another idea for an association: Dasylirion glaucophyllum, Kniphofia ‘Mango Popsicle’, Chamaerops humilis ‘Compacta’ and Agapanthus ‘White Heaven’

Did you know?

• Dasylirion was formerly food for Native Americans of Southwest deserts. Rootstock was mainly consumed.
• A fairly strong alcoholic drink called ‘sotol’ was distilled from cooked then fermented rootstocks.
• Dasylirion leaves were widely used in Native American crafts to weave baskets, make hats and toys.