Asteriscus

( ass - ter - ISS - kuss )

At-A-Glance Information

These evergreen perennial flowering plants grow best in full sun with little to moderate water, and produce yellow daisies throughout most of the year. Species are native to Europe, North America, Macaronesia, and the Middle East. Use these plants in mixed beds and borders or as pollinator plants. Although these plants are considered generally safe to grow in the garden, there is some evidence that ingestion of plant parts can be toxic to livestock.

ASteriscus Species and Varietals

The genus Asteriscus includes just nine species, and is a member of the plant family Asteraceae. Astericus growing zones vary by species; for more information see the species descriptions below. To find your zone, click here: Zone Map.

Asteriscus aquaticus (Bupthalmum aquaticum) (Sweet-Scented Ox Eye, Golden Star, Water Daisy, Seaside Ox-Eye Daisy)
This annual species is native to the Mediterranean, where it prefers to grow in coastal, dry areas. Flowers bloom April through June, and are yellow to orange in color. These are considered low-growing shrubs, great for fronting borders or in mixed plantings in coastal gardens. This species does well in USDA hardiness zones 9a-11b. 

Asteriscus daltonii (Macela)
This species is endemic to Cape Verde in West Africa, and is considered to be somewhat endangered. It grows well in USDA hardiness zones 8-11, and forms a tuft of foliage about 1.5 feet tall with small yellow flowers that bloom in spring and summertime. 

​Asteriscus maritimus (Pallenis maritima, Odontospermum maritimum) (Gold Coin, Sea Daisy, Mediterranean Beach Daisy, Estrella de Mar)
Gold Coin grows well in USDA hardiness zones 8-10 or in Sunset growing zones 9 and 15-24 and is native to the Mediterranean region and the Canary Islands. Foliage is silver-green and provides a great groundcover that gets to 1 foot tall and 4 feet wide. Tolerant of most soils and can take seaside conditions. Great for attracting bees to your garden. Variety 'Compact Gold Coin' has a more mounding habit than the species, is compact and less sprawling, and is great for pots.

Asteriscus sericeus (Nauplius sericeus, Odontospermum sericeus) (Canary Island Daisy)
Grows best in USDA hardiness zones 9a-11b or Sunset zones 16, 17 and 19-24. Gets to 3 feet tall and wide, with a shrubby habit. Leaves are silky and silvery and flowers are bright yellow. Foliage is odorous with an odd fragrance, and older leaves tend to adhere themselves to the stem and turn black. If groomed, they make a striking container plant.

Asteriscus smithii (Macela-de-Gordo)
These plants form tufts of foliage about 2.5 feet tall, and are considered critically endangered due to their very small native range and low population size.  Flowers produced by these plants are yellow and bloom in spring and summertime. Foliage is grey-green.

Caring for Asteriscus

Grow Asteriscus in a spot in the garden that receives full sun exposure; between 6 and 8 hours of direct sun each day will result in the best foliage growth and blooms. Asteriscus will adapt to most soil types, but growth is best in fertile soil amended with organic matter.  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 Asteriscus like consistently moist soil; as a general rule of thumb, make sure to water every time the top few inches of soil feels dry to the touch.

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. Taller cultivars can be cut back to encourage bushier growth. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. If plants are getting leggy, they can be cut back to encourage a bushier habit to form. 

Propagation

Asteriscus can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Asteriscus flower, follow the instructions below:

Propagating Asteriscus by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good potting medium for rooting cuttings 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.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. 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, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new plant.

Propagating Asteriscus by Seed
  1. 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.
  2. Harvest your seeds. The seed heads on Asteriscus 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. Asteriscus seeds can remain viable for up to 4 years if stored in a cool, dark, dry area.
  3. 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.
  4. 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.
An Asteriscus seed head.
Asteriscus seeds are brown and somewhat flattened.

Problems and Pests

Asteriscus plants typically do not have many pest or disease issues in the landscape, but they can have issues from time to time with the following:
  • ​Aphids
  • Mealybugs
  • Spider Mites
  • Aster Yellows
  • Powdery Mildew
  • Root Rot
For more information on these pest and disease issues, including how to treat and prevent them, consult the following pages:
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Gallery

These plants are fantastic for cottage and informal gardens; their yellow flowers will bring pollinators to the garden.
These plants produce yellow daisy-form flowers with golden-yellow centers.
Here, a taller cultivar is used in a simple bed alongside decorative rocks, Correa, and an Oak tree.

Videos

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Resources

Caring for Asteriscus maritimus
How to Grow and Care for Beach Daisy Plants
How to Grow Gold Coin - Asteriscus
Wikipedia: Asteriscus
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 176 - 177, Asteriscus