Clethra alnifolia hummingbird is a plant native to eastern North America. It is a deciduous shrub that typically grows to 6-8 tall and as wide with erect, multi-stemmed branches. It blooms in late summer to early fall, producing numerous small, white, fragrant flowers that attract both hummingbirds and butterflies. The flowers are followed by elliptical, brown seed capsules that persist into winter. The leaves are simple, opposite, oblong to ovate-oblong, and glossy dark green. The fall color is yellow to golden yellow.
Related plant:
Summersweet Clethra
About soil condition, Clethra alnifolia prefers sandy, acidic soils in full sun to partial shade, but it is adaptable to other soil types. The plant is not particularly drought-tolerant, however, and will perform best with regular watering.
So, like the other plants, Clethra alnifolia needs sunlight to grow. However, it is not a plant that needs a lot of sun. It can actually tolerate some shade. This makes it a good plant to grow under trees or near buildings. The plant will still bloom and produce its beautiful flowers even in shady conditions.
The temperature conditions that are ideal for Clethra alnifolia are those that are warm and humid. This plant does not tolerate cold or dry conditions well. The temperature range that is most suitable for this plant is between 65 and 75 degrees Fahrenheit. If the temperature falls outside of this range, the plant will not thrive.
Ideal humidity condition for this plant is 70%, however it can tolerate a range between 60-80%. If the air is too dry, the leaves will start to drop. too much humidity will make the leaves turn yellow.
Regarding fertilizer, usually the plant does not need extra nutrients added to the soil because Clethra alnifolia does well in average to poor soils. However, if you have very sandy soil, you may want to add a slow-release fertilizer or compost to the planting hole. As for root growth, this plant has a shallow root system, so be careful not to plant it where the roots will be disturbed, such as next to a sidewalk.
Pruning is an important part of keeping your Clethra alnifolia hummingbird plant healthy and looking its best. You should prune in early spring, just before new growth begins. Pruning will help to promote new growth and keep the plant from getting too leggy. You can prune back the plant by a third or more, if needed.
Propagation of Clethra alnifolia, or sweet pepperbush, is typically done through seed stratification or softwood cuttings taken in late spring. For seed stratification, the seeds need to be soaked in water for 24 hours before being placed in moist sand in a cold frame or refrigerator for 60-90 days. After this period, the seeds can be planted outdoors. For cuttings, 4-6 inch cutting should be taken from new growth in late spring and placed in moist perlite or sand. The cuttings should be kept in a humid environment until they have rooted, which typically takes 4-6 weeks.
Usually, the plant growth rate estimates are based onplantings in full sun. The growth rate of this plant is rapid when given proper growing conditions. It can grow up to 24 inches per year, but will slow down to a more manageable 12 inches if it is not given enough sun. When planted in rich, moist soil, it will spread quickly and can become invasive if not kept in check.
Common problems for this kind of plant are opportunistic pests and diseases. The most common problems include powdery mildew, rust, and leaf spot. These can be controlled with a fungicide. The other common problem is aphids. These can be controlled with an insecticide.
Source:
Clethra alnifolia 'Hummingbird' | Gardens
Clethra alnifolia 'Hummingbird' | Gardens
Clethra alnifolia 'Hummingbird' pp 8984 - Hummingbird
