Flowering Tips for the Crown-of-Thorns

Planting

• The crown-of-thorns does not respond well to excessive water. To keep your plant healthy and capable of flowering, plant it in a spot that will not be flooded by sprinklers or other water sources. Crown-of-thorns thrive in rock beds with other succulents as long as there is good drainage or in elevated beds filled with crushed rock and sand. Make sure there is at least 2 inches between plants to encourage air circulation.

Light

• A common reason why plants do not bloom is because they are not receiving proper light. The crown-of-thorns requires at least 70 percent sun exposure, according to University of Florida Cooperative Extension Service. A small amount of mid afternoon shade may improve the color of blooms if your plant is a poysean hybrid variety. Poysean hybrids, also known as Thai hybrids, have larger, roselike, pastel-colored flowers with blended colors.

Water

• Another issue that may cause crown-of-thorns not to bloom is improper watering. The crown-of-thorns should be watered minimally, and only when the top 1 inch of soil is dry. Water around the base of the plant, avoiding the foliage, and stop once the soil is moist. The plants bloom better if you allow the soil to dry out between waterings. If the temperature is below 75 degrees Fahrenheit, water less frequently and only until the soil is slightly moist. In a severe drought, the crown-of-thorns can lose blooms. To ensure the production of flowers in hot, dry weather, check the top 1 inch of soil more often and water immediately when it is dry.

Fertilizer

• Proper nutrition is crucial for flowering plants, but when plants are over-fertilized, they grow lots of new shoots quickly but fail to bloom. A crown-of-thorns should only be fertilized lightly with a balanced, slow-release fertilizer, and only twice a year, in May and October.

Pruning

• Pruning is important, but avoid removing flower buds when you prune -- without buds that are allowed to mature, your crown-of-thorns cannot grow flowers. The crown-of-thorns should only be lightly pruned two to three years after planting, during dry, cool weather. When you prune, remove only stems that are dead or tangled.

Other Considerations

• Providing proper care for the crown-of-thorns is the best way to ensure flowers, but there is one trick that may encourage blooms. The crown-of-thorns is a short day plant, meaning reducing the number of hours it spends in daylight can improve flowering. According to Ron Smith, a horticulturist at North Dakota State University, placing a paper bag over the plant around 6 p.m. and uncovering it in the morning can help it to bloom. Do this for two to three weeks and then resume normal care.