Buddleja davidii nanho blue is a shrub that is native to China. It is a member of the family Scrophulariaceae and is in the genus Buddleja. The species is named after the Rev. Adam Buddle, an English botanist and clergyman, and julius davidius, the French botanist who first described it. The nanho blue cultivar was named after the NanHO Blue Nursery in Wuxi, China, where it was developed.
Related plant:
Buddleja Davidii Pink Delight
About soil condition, Buddleja davidii nanho blue prefers well-drained soil, and it is drought tolerant once established. It can handle a wide variety of soil types, from clay to sand, as long as the drainage is good. It is not particular about soil pH, and it will even grow in nutritionally poor soil. This tough plant is also salt tolerant, making it a good choice for seaside gardens.
Not too different with other Buddleja, Buddleja davidii nanho blue thrives in full sun. It blooms profusely with blue flowers that are loved by bees and other pollinators. This heat-loving plant is drought tolerant once established and does not require much maintenance.
The temperature condition that is best for Buddleja davidii nanho blue is warm. This plant does not like to be in cold temperatures for long periods of time. It is best to keep this plant in a temperature that is above 60 degrees Fahrenheit. If the temperature drops below this, the plant will start to experience stress.
Ideal humidity condition for this plant is around 50%. If the humidity drops below 40%, the plant will start to experience stress and may even die. If the humidity rises above 60%, the plant may start to experience fungal growth.
Regarding fertilizer, usually the plant does not need much. If you have used a good quality potting mix with some organic matter already in it, you may not need to fertilize at all the first year. If you do decide to fertilize, use abalanced fertilizer such as 10-10-10 at half the recommended strength. It is best to apply fertilizer in early spring and again in mid-summer. If you live in an area with very hot summers, you may want to skip the mid-summer fertilizer application. As for watering, this plant is quite drought tolerant once established. In fact, if you water too much, you may end up with root rot. When watering, make sure to water deeply and then allow the soil to dry out somewhat before watering again.
Pruning is an important aspect of caring for Buddleja davidii nanho blue. While the plant does not require frequent pruning, it is important to prune it every few years to encourage new growth and to keep the plant healthy. When pruning, be sure to remove any dead or dying branches, as well as any branches that are crossing or rubbing against each other. Trim back any long branches to encourage a more compact growth habit.
Propagation of Nanho blue buddleja is best done through softwood cuttings taken in late spring or early summer. The cuttings should be taken from new growth that is just beginning to harden off and should be about 4-6 inches in length. Use a sharp knife or pair of shears to make a clean cut just below a node, and then remove the lower leaves so that only two or three leaves remain on the cutting. Dip the cut end of the cutting in rooting hormone, and then plant in a moistened rooting medium. I like to use a mix of perlite and vermiculite, but you can use peat moss or sand as well. Place the cutting in a warm, bright location out of direct sunlight, and water regularly to keep the rooting medium moist but not soggy. In 4-6 weeks, you should see new growth, at which point you can transplant the cutting into a pot or into your garden.
Usually, the plant growth rate is in the spring and summer months. The plant can grow quite rapidly, especially when young. However, the rate at which it grows will vary depending on the variety of plant.
Common problems for this kind of plant are usually down to cultural issues in its growing environment. These include incorrect soil type, lack of drainage, planting in too much shade, insufficient watering or too much fertilizer. If any of these are causing problems, the plants will often show signs of stress such as yellowing leaves, wilting or stunted growth. Often, simply improving the growing conditions can alleviate the problem.
Source:
Butterfly Bush (Buddleia (Buddleja) davidii) - uaex.uada.edu
JC Raulston Arboretum - Photographs of Buddleja davidii 'Nanho Blue'
Buddleja davidii (Buddlejaceae) - HEAR species info
