HOHERIA: An Accessible Winter Herb

Posted: August 2022
Author: Phil Rasmussen | M.Pharm., M.P.S., Dip. Herb. Med.; M.N.I.M.H.(UK),  F.N.Z.A.M.H. 
 

Hoheria populnea (hoheria), otherwise known as houhere, hōhere, lacebark and ribbonwood, is a variable species which has many different varieties and often hybridises with the closely related Hoheria angustifolia, H. equitum, H. ovata and H. sexstylosa. It is a fairly common and easy-to-grow native tree that is often planted, has attractive and scented white flowers in summer and its bark contains a fibre that was widely used to make clothing or hats.

Of course, what makes hoheria so distinctive to herbalists is its rich content of what we call polysaccharide hydrocolloids (mucilage). The presence of these constituents is apparent from the formation of mucilage and the development of a sweet taste when the leaves are chewed and polysaccharides are broken down to rhamnose and galactose. While all parts of the tree are rich in these polysaccharides, the leaves are most amenable to sustainable harvesting and have plenty of mucilage in them.

As with the polysaccharide colloids found in other well-known plants such as marshmallow, slippery elm, comfrey and psyllium, hoheria has widespread topical applications, including for sores, abscesses and burns. It also has a particular affinity for congestive conditions of the chest or airways. This is probably largely due to its action as an expectorant, which are medicines that decrease the viscosity and help to free up tenacious mucus or increase mucus secretion in the case of a dry, irritant and unproductive cough. By acting locally on the bronchial tract itself to increase lubrication, the cough can be made to be more productive, which is often (but not always) a desirable outcome. Encouraging the natural eliminative processes of the ciliary network to prevent or remove unwanted airborne particles or microbes, is generally a preferred approach to suppression when it comes to coughs.

While quite often large doses of hoheria are required to have such an expectorant action, as with all expectorants, if the dose given is too high an emetic or mild laxative effect can be seen. It is, however, generally a very safe herb to use for a range of bronchial conditions (especially dry and painful coughs), and makes an ideal native plant alternative to marshmallow. It is also useful in children’s cough mixtures due to its sweet taste and seems to combine well with most other cough herbs, including kumerahou, white horehound, elecampane and hyssop.

In terms of dosage, typical doses of a 1 in 4 fresh leaf tincture for adults range from 5 to 20mls daily, although higher amounts can sometimes be given in divided doses.

If you’ve not used hoheria in your cough or chest formulations previously, I’d encourage you to try it. It is a readily available, versatile and sustainable local phytomedicine.

Phil Rasmussen

References:

1. Brooker SG, Cambie RC, Cooper RC. New Zealand Medicinal Plants. Heinemann Publishers, Auckland, 198
2. Riley M., “Maori Healing and Herbal: New Zealand Ethnobotanical Sourcebook”, Viking Sevenseas, Paraparaumu, N.Z., 1994.
3. Rasmussen PL, New Zealand Native plants and their clinical applications for respiratory conditions, Phytomed Seminar, June 2015.
4. Sims IM et al, Int J Biol Macromol. 2018 May;111:839-847.