Bob's News and Musings: Conifer Understocks From Abies Through Tsuga

Grafting involves attaching a twig from the desired plant to a seedling that is compatible with that twig. After the twig combines with the seedling (cambiums grow together), the portion of the seedling above the graft union is removed, and the twig becomes a Dr. Frankenstein sort of plant with the twig using the seedling’s root system as its own.

The twig is called a scion, while the seedling is called an understock. The origin of the term scion can be traced back to its definition as “the descendant of a notable family.” However, the source of the term understock is more evident since it is the lower or underpart of the newly created plant.

Here I want to focus on conifer grafting. I will have comments on deciduous grafting in a future newsletter.

The choice of understock is relatively simple, but some considerations need to be followed. The species of the cultivar must be related to the seedling’s species, and the process of grafting can have various effects on the resultant plant.

Cultivars of Abies (true firs) are compatible with any of the various Abies species of understock. However, the actual selections are restricted to a few species mainly due to availability considerations.

For example, three fir species are most commonly used in North America. Abies balsamea is possibly the most popular species used. The plants created cannot be grown in warmer climates as the roots cannot withstand constant high temperatures and hot sun. Abies fraseri is preferred in the northwest since greenhouses are exceptionally humid during the grafting season, and winters are mild and wet. This species appears to tolerate these conditions better than balsamea. Cultivars propagated on this species can be grown in a broader range of climates.

Read the full article here.

Bob's News and Musings. Article presented courtesy of ACS member Bob Fincham, and originally posted at https://www.robertfincham.com/ .