How to Grow Ageratum Flowers

Ageratum Flower

Growing Ageratum in Your Home Flower Garden

Ageratum flowers are among the prettiest garden blues, growing well in sun or partial shade, from early summer to frost. Growing Ageratum is easy. So, they are excellent plants for beginner gardeners. They produce a profusion of long-lasting, fluffy flowers all season long. In the fall, the plant will drop ageratum seeds, to reseed the area for next year. Annual ageratum plants are native to tropical regions of South and Central America.

Their small size and bright, cheerful color make Ageratum flowers good candidates for both rock gardens and flower beds. Use them as an edging plant for flower garden borders, too. Try growing Ageratum plants in containers, too. They will be right at home on your patio or deck. 

Ageratum Plant Specifics

Flower Colors: The blues are the most popular, providing a colorful accent. Flower colors also include pink and white. 

Flowers Bloom: June through frost

Plant Height: Compact plants grow just 6-8 in. tall. Some varieties grow up to 30 inches tall. The plant grows 6 – 18 inches wide.

Light Requirements: Full sun to partial shade

Ideal Soil pH: 6.0 – 7.5.

Hardiness Zones: 2 – 11

Edible Plant: No

Toxicity: Harmful to humans and pests

Other Names: Floss Flower

Annual, Ageratum houstonianum

Ageratum Plant Medicinal Uses

Ageratum plants are harmful to humans and pets. However, it does have medicinal applications. They include: 

  • Antioxidant
  • Antiviral
  • Anti-inflammatory uses
  • Helps healing wounds
  • Healing skin infections
  • Antifungal

Ageratum Plant Propagation

Ageratum flowers are grown from seeds. Sow Ageratum seeds outdoors, after all danger of frost. Or, start indoors 6-8 weeks before the last frost date for your area. We recommend an indoor start. This will result in earlier blooms.

Cover seeds with 1/8″ of light garden soil or seed starting soil. Then, water lightly after sowing seeds. The seeds are just below the surface of the soil. So initially, you do not have to water them deeply. Keep the top of the soil moist. After the seedlings sprout, water more deeply.

At the end of the season, it is easy to collect seeds from the dead blooms for planting next year.

Gardening Tip: Select a location where annual ageratum plants can grow for years. The plants are very good re-seeders. If allowed, the spent blooms will drop seeds for next year’s crop of these beautiful flowers.

How to Grow Ageratum Flower Plants

Growing Ageratum flowers is easy. They are low maintenance flowers.

Ageratum prefers full sun to partial shade. They will tolerate a fair amount of light shade.

The plants will do well in both average and poor soils. Mix a generous amount of compost or peat moss into the planting site.

Space plants 6-8 inches apart. Water well, when planting.

They are tolerant of dry soil conditions. Water the plants when the top of the soil is dry. Keep soil moist, but not wet during dry seasons. Water the plants at ground level. Avoid getting water on the leaves, if possible. Water on the leaves can promote fungal diseases.

Add a general-purpose fertilizer once or twice a season. Apply a granular, general-purpose fertilizer. If the leaves begin to yellow, there is likely too little fertilizer in the soil. For a quick boost, apply a liquid fertilizer. 

Growing Ageratum Plants in Flowerpots and Containers

Ageratum plants are at home in flowerpots indoors or out. Select a flowerpot style and color that fits the location where it will be located. Then, fill it with a general-purpose potting soil. The container should have a drain hole to allow excess water to drain away. Then, plant it into the container. After planting, water it thoroughly. Your container has limited fertilizer and moisture in the soil.  Keep the soil moist, but not wet. Monitor the soil conditions every couple of days, especially in hot, dry weather. Fertilize the plant every month. If the leaf color begins to fade, or plant growth slows down, apply a quick boost of liquid fertilizer.

Pruning Ageratum Plants

Pruning ageratum plants and flowers is not an absolute requirement. However, it has benefits. Pruning makes the plant look more attractive. And, removing spent blooms signals the plant to produce more blooms. 

How to Deadhead Flowers.

Insects and Plant Disease

The most common insect problem is mites. Most insect problems can be effectively treated with insecticidal soaps and milder insecticides like Sevin.

Disease problems are not very common. high humidity can cause fungal problems. If problems occur, treat the plants early with a fungicide as needed.

Also see: Plant Problems – causes and cures

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