Rhododendron arborescens

The official credit for the discovery of R. arborescens goes to Frederick Traugott Pursh and John Bartram. It was first observed in John Bartram's garden in Philadelphia as well as Blue Mountain, Pennsylvania.[2]

It has also been mentioned that the plant was initially noticed by André Michaux in 1795 in the state of North Carolina. However, after further investigation, no more species were found in his conservatory. Therefore, the recognition for the discovery of the plant was given to Frederick Traugott Pursh and John Bartram.[2]

Rhododendron arborescens was first named Azalea arborescens by Pursh in 1814. However, John Torrey renamed it Rhododendron arborescens in 1824 because he believed that it should not be taxonomically separated from the rhododendrons.[4]

Immature flowers of Rhododendron arborescens

Rhododendron arborescens is a deciduous shrub up to 18 ft (5.5 m) tall, with terminal inflorescences growing from the end of the stems. These plants also generally have yellowish-brown twigs. The green, waxy leaves are 1.75–3 in (4.4–7.6 cm) long, oval and entire with round tips and hairy midribs. Plants found at higher altitudes are generally smaller with smaller leaves. The plant produces from 3 to 7 flowers after a white or blue shade has appeared on the leaves. The stigmas are quite visible all the way up to the petals.[2]

It is distributed in the eastern part of the United States. They are known to grow in parts of West Virginia, Pennsylvania, Tennessee, North Carolina, Georgia and Alabama. They are found among streams near mountains or moist forests. Rhododendron arborescens are generally known as late bloomers. They have a range of blooming from early April till September.[2]

R. arborescens grows best in soil that is slightly acidic at a pH of 5.5-6. It does not grow well in excessive water and drainage is necessary for healthy growth. It is tolerant of full sunlight but must not be overexposed. It is beneficial to plant it with the roots slightly above the ground and accumulating soil up to the plant roots. Organic matter such as sawdust and pinebark may aid the growth of the plant. Depositing a few inches of pine bark or wood chips may help in keeping moisture and preventing weeds from growing around the plant. However, mature R. arborescens do not need to be fed with fertilizer.[5]

This plant has gained the Royal Horticultural Society's Award of Garden Merit.[6][7]

Structure of Grayanotoxin

R. arborescens contains andromedotoxins, specifically known as grayanotoxins which are water-soluble diterpenoid compounds. Both the leaf and flowers of this plant are sources of toxins. Consuming as little as 3 milliliter of nectar per kilogram body weight may be highly pernicious.[8]

Mechanism

Andromedotoxins bind to the Na channels of cell membranes which increases the influx of sodium in the cell and causes extended depolarization. This causes sodium channels to accommodate calcium influx into the cell which also results in depolarization.

Cardiac Action Potential

Possible Treatments

One way to possibly treat it is to detoxify the body. Emesis, or forcefully vomiting, is one way to rid the body of harmful compounds. Another way to treat it may be to replace the internal body fluid and receive respiratory support. Quinidine is an example of a Na channel blocker which may be helpful in curing heart block.[8]

Structure of Quinidine