Grewia
( GREW - ee - uh )
At-A-Glance Information
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Grewia occidentalis is a species of flowering evergreen shrubs, commonly called Lavender Starflower or Crossberry. They need regular water and full sun to perform well, and their flowers will attract butterflies to your garden. These natives of South Africa, bloom in late spring through fall. Great as espalier subjects, Lavender Starflower can also be used as a hedge or screening plant. Unstaked, they will reach between 6-10 feet tall and 4 feet wide. Grewia occidentalis grows well in zones 8, 9, 12-24, H1 and H2 (to find your zone, click here: Zone Map), and can tolerate winds. The genus Grewia includes about 320 species and is a member of the plant family Malvaceae, and was named by Carl Linnaeus to honor the botanist Nehemiah Grew.
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Caring for and pruning Grewia shrubs
Lavender Starflower should be planted in springtime in full sun in well-draining soil. Soil should be on the acidic side, with a pH of between 5.5 and 8.5. Although Lavender Starflower can really grow in any soil, they do benefit from having their roots in soil that is rich in organic matter. Do not allow the soil to dry out completely in between waterings; keep the soil moist but not wet, especially during flowering and fruiting periods. Crossberry shrubs like warmer temperatures and humidity in the air. Protect these shrubs from frost and very cold temperatures, especially cool, drying winds. If grown in containers, it is a good practice to bring the shrub indoors over the winter months to protect it from possible damage. These shrubs and small trees grow quickly; do any major prunings necessary after flowering is over in autumn, and make sure to not remove more than a third of the tree at a time. These shrubs can be trained into single-trunked small trees or tied over arbors and trellises, and can also be used as container trees on patios and along walkways as well as used as bonsai. Fertilize three times a year with a slow-release fertilizer good for acid-loving plants.
Harvesting Grewia
The berries produced by these shrubs are edible, and are used for flavoring yogurts and beers in some parts of the world. They can be eaten raw; they are sweet and tart, reminiscent of apricot. Crossberries can also be dried and eaten as a raisin-like snack. To harvest your Crossberries, wait until they have begun to turn a little brown and they are slightly squishy. Then, remove them from the shrub, rinse them, and eat them.
Harvesting Grewia
The berries produced by these shrubs are edible, and are used for flavoring yogurts and beers in some parts of the world. They can be eaten raw; they are sweet and tart, reminiscent of apricot. Crossberries can also be dried and eaten as a raisin-like snack. To harvest your Crossberries, wait until they have begun to turn a little brown and they are slightly squishy. Then, remove them from the shrub, rinse them, and eat them.
Propagation
Grewia occidentalis 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 shrub, follow the instructions below:
Propagating Grewia by Cutting
Propagating Grewia by Seed
Propagating Grewia by Cutting
- 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. 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.
- 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.
- 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.
- 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 shrub.
Propagating Grewia 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. 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.
- Harvest your seeds. They are contained within the fruits left behind after flowers have faded, and will need to be extracted from the pulp and rinsed before using.
- 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 2-3 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 over 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
The seeds on Lavender Starflower shrubs are contained inside fruiting bodies that appear after flowers have faded.
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Grewia occidentalis seeds.
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Problems and Pests
Grewia occidentalis shrubs
- Scale
- Mealybugs
- Aphids
Gallery
These shrubs can be espaliered onto trellises against walls.
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Once you see these shrubs in bloom, it will be easy to figure out why they are called Lavender Starflower.
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These fast-growing sprawling and climbing shrubs are great for filling in areas of the garden.
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Videos
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How to grow Crossberry in a container.
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All about Lavender Starflower.
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How to repot your Crossberry shrub.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Page 348, Grewia occidentalis
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