Iberis

( eye - BEAR - iss )

At-A-Glance Information

Commonly known as Candytuft, plants in this genus reach a foot tall and hail from southern and western Europe. These flowers need full sun to partial shade and regular water to perform well in the garden. They will attract butterflies and other pollinators to the landscape. Both annual and perennial varieties bloom freely from early spring through summer. Annuals prefer areas where summer nights are on the cooler side. These versatile plants can be used as small-scale groundcover, as edgings, in rock gardens or containers, and are great as cut flowers. Take care when planting these flowers in the garden, as they are mildly poisonous to humans and pets.

Iberis Species and Varietals

The genus Iberis is a member of the plant family Brassicaceae and includes 30 species. They are closely related to species in Lobularia, Erysimum, Matthiola, Brassica, and Raphanus. Candytuft grow best in USDA hardiness zones 3-9 or Sunset growing zones 1-24, though this varies somewhat depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Iberis amara (Wild Candytuft, Rocket Candytuft, Bitter Candytuft, Annual Candytuft)
This species is native to Belgium, France, Germany, Great Britain, Italy, Spain and Switzerland. It has been introduced to and naturalized in many other areas around the globe. This species typically reaches between 4 and 12 inches tall when in bloom and produces green foliage and white flowers. There are also some garden varieties available in deeper shades of pink, violet, or fuchsia. Best in USDA hardiness zones 6-9. This species is considered invasive in New England and the Mid-Atlantic region of the United States and southern Canada.

Iberis gibraltarica (Gibraltar Candytuft, Candytuft, Evergreen Candytuft)
Best in USDA hardiness zones 6-9 or Sunset growing zones 4-9 and 14-24. Stems on this plant bear flat clusters of light pink to purple flowers which sometimes have white centers. They are native to North Africa, and are the national flower of Gibraltar. This species is perfect for rock gardens and mixed borders. Individual plants reach up to 8-12 inches tall and 12-18 inches wide.

Iberis saxatilis (Rock Candytuft)
This species is native to southern Europe and northwestern Africa, and is typically used as an ornamental in rock gardens. It has a cascading growth habit, and can be evergreen or semi-evergreen depending on the climate it is grown in. Flowers are typically white, aging to pinkish or purplish. Stems form adventitious roots where they touch soil. Great for alpine gardens. This species reaches up to 3-6 inches tall and 12 inches wide.

Iberis sempervirens (Evergreen Candytuft, Perennial Candytuft)
This species is a perennial favorite and grows to 12 inches tall and about as wide. Leaves are dark green and endure throughout the year. These plants are native to Morocco, Algeria, Syria, Turkey, Spain, France, Italy, Romania, and the Balkan Peninsula. Flower clusters of white are perfect for adding softness to fresh arrangements. Varieties are outlined below.

'Alexander's White'
To 6 inches tall with delicate foliage.

'Little Gem'
Reaches 4-6 inches tall.

'Purity'
6-12 inch tall plant with a spreading habit.

'Snowflake'
12 inches tall and 3 feet wide. Large flower clusters on short stems.

'Snow White'
12 inch tall, 24 inch wide mound.

'Tahoe'
An upright grower that reaches 10-12 inches tall and just as wide.

Iberis umbellata (Globe Candytuft, Garden Candytuft, Annual Candytuft)
This species is a bushy annual that grows to 12-15 inches tall and 9 inches wide. Flowers come in a variety of colors including slalmon, white, pink, rose, red, purple, and lilac. Variety 'Candy Cane' (pictured) has rose, purple, lilac and white flowers and the Dwarf Fairy series reaches just 6 inches tall.

Caring for Iberis

Take care when planting these flowers in the garden, as they are mildly poisonous to humans and pets. Plant annual species in spring, and perennial species in spring or fall. Iberis, or Candytuft, does well in full sun exposure. These plants can grow well in partial shade, but will flower best when they receive between 6 and 8 hours of sun each day. In warmer climates, provide some late afternoon shade when temperatures are the warmest. They need excellent drainage to thrive; in their native range, they typically grow in gravelly or sandy alkaline soils. Iberis prefers soil to have a pH of between 6.0 and 8.0 (slightly acidic to slightly alkaline). 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. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered drought-tolerant, able to get by on rainwater for much of the year with supplemental deep waterings during extended periods of dry weather.

Fertilize yearly in early springtime with a 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 Iberis plants is simple: remove spent blooms and any unsightly foliage. These plants bounce back well from pruning. Late in the season, plants can have a tendency to get leggy, especially if they are grown in too much shade. Plants can be cut down to about four inches tall at this point, and a flush of new growth and flowering will be triggered. Avoid pruning after late summertime, as the plant will set its buds for the coming season during this time. Every few years, dig up and divide mature plants in fall to prevent the center of the plant from drying out and creating a 'bald spot'. Annual species are typically pulled and composted at the end of the growing season or can also be left in place to enrich soil. Perennial species can live for between 5 and 10 years in the landscape before needing to be replaced.

Propagation

Iberis can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division 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 Candytuft, follow the instructions below:

Propagating Iberis 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 plants are pretty easy to spot, they're left behind after flowers have faded. Once they have dried out and begun to split open, you can harvest the seeds inside. Cut them 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 continue to split open and 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.
In either late winter or early springtime, get your container prepared. 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 2-6 weeks 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 65 and 72 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.

Propagating Iberis by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root(s). Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers. Once the roots are untangled, separate your plant into segments, ensuring that each one has at least one thick root section attached.
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 in the next growing season.

Candytuft seed heads dry out and turn brown before dropping seeds.

Iberis seeds are typically light brown to tan in color and tiny.

Problems and Pests

Certain Iberis species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Iberis, or Candytuft, is susceptible to developing issues with the following pests and diseases in the landscape: