Hibiscus syriacus 'Blue Bird'
Rose of Sharon, Althaea, Shrub Althea
Type Shrub, woody plant
Hardy range 5B to 9A
Height 10' to 12' / 3.00m to 3.60m
Spread 6' to 10' / 1.80m to 3.00m
Growth rate Slow
Form Upright or erect
Exposure Partial shade or partial sun to full sun
Persistence DeciduousBloom Color Blue
Bloom Time Summer
The flowers are very showy.
EnvironmentThis plant tolerates some drought, occasional wetness and some salt.
This plant will grow in dry to occasionally wet soil.
Suitable soil is well-drained/loamy, sandy or clay.
The pH preference is an acidic to neutral (less than 6.8 to 7.2) soil.
Leaf Color GreenFall Color No change in fall color
Culture Notes Easily grown shrubs usually planted in the perennial garden because of the abundance of colorful flowers. Too much or too little water or over fertilization will cause buds to drop from this plant. This plant is capable of self-sowing to the point of being a nuisance if the soil beneath is good. Pollen can cause slight to mild allergy symptoms.
Plants often have poor root systems which cause the plant to fall over as it grows taller. This often originates in the nursery when plants are held in containers too long. This can be avoided by choosing plants that are small for their container and slicing any roots that circle the outside of the container. Some growers also use alternate container designs specially designed to reduce the amount of circling roots.
Planting and establishing shrubs The most common cause of young plant failure is planting too deep. Plant the root ball no deeper than it was in the nursery. In most instances, the root flare zone (point where the top-most root in the root ball originates from the trunk) should be located just above the landscape soil surface. Sometimes plants come from the nursery with soil over the root flare. If there is soil over this area, scrape it off. The planting hole should be at least twice the width of the root ball, preferably wider. In all but exceptional circumstances where the soil is very poor, there is no need to incorporate anything into the backfill soil except the loosened soil that came out of the planting hole. Never place ANY soil over the root ball. If a row or grouping of plants is to be installed, excavating or loosening the soil in the entire bed and incorporating organic matter enhances root growth and establishment rate.
Weed suppression during establishment is essential. Apply a 3-inch thick layer of mulch around the plant to help control weed growth. Keep it at least 10 inches from the trunk. If you apply it over the root ball, apply only a one or two inch layer. This allows rainwater and air to easily enter the root ball and keeps the trunk dry. Placing mulch against the trunk or applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water. Regular irrigation through the first growing season after planting encourages rapid root growth, which is essential for quick plant establishment.
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