Watsonia

( wot - SOH - nee - uh )

At-A-Glance Information

This genus of perennial flowering plants grows from corm and needs full sun and regular waterings during its blooming and growing periods. They are native to South Africa, and their flowers will attract hummingbirds and butterflies to the garden. Flowers are fragrant, red-orange and trumpet-shaped, and similar to Gladiolus. Take care when planting these in the garden, as they are known to be invasive in some areas of the world, and there is evidence that they may be toxic to animals.

watsonia Species and Varietals

The genus Watsonia is a member of the plant family Iridaceae and includes 56 species. Watsonia is named for Sir William Watson, 18th century British botanist. The best growing zones for Watsonia are 4-9 and 12-24. To find your zone, click here: Zone Map.

Watsonia borbonica (Watsonia pyramidata) (Cape Bugle-Lily)
This deciduous species of Watsonia blooms in late spring, producing flowers in pink, rose-red, or white. Hybrid varieties are available with flowers in pink, red and lavender. Foliage will die back after blooms fade, and reappear the following autumn. During summer dormancy, these plants prefer dry soil, but will take water if the soil is particularly well-draining.

Watsonia marginata (Fragrant Bugle-Lily)
These perennial plants are native to the Cape Provinces of South Africa, and is widely grown across the world as a garden ornamental plant. Individual plants produce three to four erect leaves that are blue-green with thick, yellow margins. Flowers can be shades of pink, red, or white. 

Watsonia meriana (Bulbil Bugle-Lily, Wild Watsonia)
Native to South Africa, these plants are well-known as ornamentals around the world, and are considered an invasive species in areas where they have escaped garden cultivation. Flowers produced by this species are orange to reddish-purple and bloom on spiked inflorescences.

Watsonia pillansii (Watsonia beatricis) (Beatrice Watsonia)
This species is evergreen and blooms in the middle of summer with flowers in bright red-apricot. Hybrids come in hues from red to peach. After bloom fades in summer, provide less water and ensure the plant's roots are in soil that is well-draining.

Caring for watsonia

Watsonia plants can be purchased as corms (moreso with the deciduous species) or as specimens from a reputable nursery. Set corms 4 inches deep and 6 inches apart in early fall. Plant them in full sun; ideally, they like to get between 6 and 8 hours of sun each day. In particularly warm climates, provide some shade in the late afternoon. Ensure that soil is well-draining, rich in nutrients and organic material, 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, Watsonia flowers like a moderately moist substrate. As a general rule of thumb, water whenever the top inch or two feels dry to the touch. Make sure that soil drains well, as they do not like to have soggy roots.

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. On perennial species, dead, damaged, and diseased foliage can be cut back at any time during the active growing season. Allow leaves to die back completely on deciduous species before removing it. Watsonia can be left undisturbed for many years, though the deciduous type above (Watsonia borbonica) can be dug up after leaves fully fade and stored indoors during its dormant period in summertime. When Watsonia is grown in a cramped space, such as a tight border or container, they may need to be divided every few years to ensure they stay healthy. 

Propagation

Watsonia, or Cape Bugle Lily, can be propagated by division or 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, especially if you are propagating a hybrid cultivar. To propagate your Cape Bugle Lily, follow the instructions below:

Propagating Watsonia 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. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
  2. 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.
  3. 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.
  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 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 Watsonia 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 (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:
  1. 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.
  2. 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.
  3. 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.
  4. 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.

Problems and Pests

Watsonia ​plants can be susceptible to developing issues with the following pests and diseases in the landscape:
  • Rust
  • Whitefly
  • Aphids
  • Root Rot
For more information on these pests and diseases, including how to treat and prevent them, consult the following pages:
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Gallery

Some Watsonia species produce large tufts of foliage that emanates from a central point.
Here, Watsonia adds architecture, height, and interest to an informal garden space.
Watsonia corms.
These plants produce eye-catching bright flowers that are favorites of hummingbirds.
Watsonia adds a tropical look to landscapes.
The foliage of these plants is quite architectural.

Videos

Learn all about these beautiful garden ornamentals.
Watsonia meriana is in bloom in this video.

Resources

Watsonia
Watsonia - Growing Guide
Watsonia meriana
How to Grow Watsonia - Cape Bugle Lily
Plant Management: Watsonia
Wikipedia: Watsonia (plant)
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 654, Watsonia