Astelia

( ass - TEEL - ee - uh )

At-A-Glance Information

This genus of evergreen perennial includes species grown for their silky foliage that contrasts well with other commonly planted low grasses and mounding plants. They need full sun or partial shade and moderate water to perform well. Species are native to islands in the Pacific, Indian, and South Atlantic Oceans, Australia, New Zealand, and southern South America. Inconspicuous flowers bloom in springtime on female plants only, and are followed by showy berries. Astelia plants are wonderful in container arrangements or added to perennial border gardens, and are salt and drought tolerant.

Astelia Species and Varietals

The genus Astelia is the type genus member of the plant family Asteliaceae, and includes between 25 and 30 species. The best Sunset growing zones for Astelia are USDA hardiness zones 8-11 or Sunset growing zones 5, 6, 14-17 and 19-24. Growing zones vary somewhat depending on the species cultivated; for more information see the species descriptions below. To find your zone, click here: Zone Map.

Astelia alpina (Pineapple Grass, Silver Astelia, Perching Lily)
These plants are perennials which grow in dense clusters called mats, typically in alpine bogs. They are native to New South Wales and Victoria, and were first formally described by Robert Brown. Foliage is silvery, and is similar in appearance to that of a Pineapple plant. Individual plants reach 4-6 inches tall and 6-8 inches wide. This species is best in USDA zones 7a-10b and is not considered cold-hardy.

Astelia banksii (Shore Astelia, Coastal Astelia, Silver Sword, Wharawhara, Kowharawhara)
This species of Astelia reaches 2-3 feet tall and 3-4 feet wide at maturity, and has arching silvery-green leaves. Flowers are greenish and followed by purple-black berries. Best in light shade. These plants do well in USDA growing zones 8-11 and are hardy down to 20-25 degrees Fahrenheit.

Astelia chathamica (Astelia nervosa chathamica) (Silver Leaf, Chatham Islands Kakaha, Maori Flax, Silver Spear, Moriori Flax)
This variety of Astelia grows to 4 feet tall and 6 feet wide, with shiny, silvery leaves and cream colored inconspicuous flowers that bloom in clusters 20 inches tall. Berries that follow blooms are orange. Best in USDA zones 8b-11 or Sunset zones 5-6 and 18-24.

Astelia fragrans (Bush Lily, Bush Flax, Kakah)
Native to New Zealand, this species produces long, sword-like leaves with reddish midribs. Between October and November in the plant's native range, they produce clumps of fragrant green flowers. Yellow-orange fruits follow in summertime. The plant was first formally described by William Colenso in 1883. This species grows well in USDA hardiness zones 8-10.

Astelia nervosa (Mountain Astelia, Bush Flax, Kakaha)
This variable species typically reaches 2-3 feet tall and twice as wide with foliage that is silver-green on top and bronze with green midribs underneath. Leaves can reach 7 feet long. Flowers are green-yellow to bronze-purple and bloom atop tall stalks, with orange berries that follow. Variety 'Wetland' (pictured right) is more compact than the species, and has a reddish tint on the normally silver-green foliage. These plants do well in light shade. Mountain Astelia is best when grown in USDA hardiness zones 8-11.

Astelia nivicola (Red Mountain Astelia, Red Devil Astelia, Morice's Astelia, Morice's Kakaha)
Clumps of foliage reach 1.5 feet tall and 2 feet wide Green leaves have maroon stripes and a silvery sheen. Great for containers. Red Mountain Astelia grows well in USDA hardiness zones 7b-10b. Cultivar 'Red Gem' is a popular ornamental variety for gardens.

Caring for Astelia

Astelia plants are grown in either full sun or partial shade; the amount of sun needed varies depending on the species and cultivar grown. Make sure to check plant tags before choosing a planting site. Astelia plants appreciate shelter from drying winds and frost, which can damage foliage. These easy-care perennials need well-draining soil that is rich in nutrients and has a pH of between 6.0 and 7.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered to be drought tolerant, able to get by on rainwater alone for much of the year with supplemental waterings during extended periods of drought.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. If you will be collecting seed for propagation, make sure to leave some flower spikes to mature. After a few years, especially if these plants are grown in cramped spaces or containers, Astelia plants will need to be divided. For instructions on how to successfully divide your Astelia plant, see the Propagation section below.

Propagation

The most straightforward way to propagate Astelia is through division of existing plants. This process will need to be completed every year to every few years (depending on the species and cultivar grown and where it is planted) to ensure ongoing health. Astelias can also be propagated via seed, though this method can result in offspring that do not have the exact same qualities as the parent plant. To propagate your Astelia plant, follow the instructions below.

Propagating Astelia by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, and pots (12 inch pots will do, and these are only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall (after the plant has entered dormancy and been cut to the ground, but before it has begun its new spring growth), and needs to be done every four to five years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the roots. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your gloved fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divisions and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout!

Propagating Astelia by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seed heads on Astelia plants are left behind after flowers have faded. Once they have dried out, you can harvest the seeds. Cut the flowering heads off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to release the seeds contained inside. Once they have been released, take them out of the bag and put them in a container so you can work with them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.