How to Care for a Sun Star Flower

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Sun star's blooms last up to three weeks as cut flowers.
Image Credit: Ryzhkov/iStock/Getty Images

When the garden cries out for exotic color, the flame-orange sun star plant (Ornithogalum dubium) more than meets the challenge. This South African bulb, perennial in U.S. Department of Agriculture plant hardiness zones 7a through 10b, reaching just 12 to 15 inches high. In late winter or spring, depending on location, clusters of dainty, star-shaped spring blooms nod above its drooping, grassy leaves. Give easy-care orange sun star a sunny site with well-drained soil where its toxic compounds won't threaten children or pets.

Fertilizer Requirements

A sun star's bulb contains enough nutrients for its first growing season. Additional fertilizer isn't necessary, but working 2 tablespoons of 0-46-0 superphosphate fertilizer into the surrounding 10 square feet of soil prior to planting *encourages strong root development. Sprinkle the granules evenly over the soil's surface, till them into the top 6 to 8 inches and water thoroughly.

An established sun star benefits from light fertilizing between the time its flowers fade until its new spring growth emerges. Every other month, dose it with a half-strength solution of water-soluble fertilizer. A 15-5-15 formula works well.

One manufacturer recommends mixing 1 teaspoon of its fertilizer granules in 1 gallon of water, so the sun star would get 1/2 teaspoon. Mix the solution in a 1-gallon watering can and pour it evenly around the base of the plant. Regardless of the brand, use only one-half of the recommended amount. Overfertilizing sun star causes brown leaf tips.

Watering Sun Star

Sun star thrives in evenly moist soil but tolerates dry soil much better than wet. One inch of weekly water when it's actively growing is ideal. Give it supplemental water only when rainfall isn't enough.

A rain gauge keeps track of rainfall. Check weekly and water when the gauge's moisture level measures less than 1 inch. One inch of water amounts to about 6 gallons for every 10 square feet of soil. If the gauge reads 1/2 inch, for instance, give the sun star 3 gallons of water for every 10 square feet. Water slowly, pausing if necessary to let the soil absorb the moisture.

Stop watering when the blooms die back in early summer, when rising temperatures trigger the plant's dormancy. Resume when the new leaves emerge in fall or winter.

Post-Bloom Pruning

As each flower cluster fades, cut it off at the base of the stem. Sun star's leaves continue photosynthesizing food for the bulb to store over the winter. As summer progresses, they gradually turn yellow and die back. When they're dead, cut them back at the base.

Use clean, sharp stem cutters to remove the stems and leaves. Disinfect them in rubbing alcohol between cuts to avoid spreading disease. Wear waterproof gloves while pruning to protect your skin from sun star's potentially irritating sap.

Potential Problems

Insects rarely trouble sun star. Rust and leaf spot diseases are occasional problems. Prune any leaves with pale or brownish spots and dispose of them in sealed plastic bags. Disinfect pruning tools between cuts in rubbing alcohol and after finishing.

Keep the soil around the plant clear of debris; it may harbor the rust or leaf-spot fungi. Although unsightly, the diseases rarely do enough damage to warrant fungicide treatment.

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Judy Wolfe

Passionate for travel and the well-written word, Judy Wolfe is a professional writer with a Bachelor of Arts in English literature from Cal Poly Pomona and a certificate in advanced floral design. Her thousands of published articles cover topics from travel and gardening to pet care and technology.