Aerial roots (more!)

From: Peter Randall <prandall at networx.com.au> on 1997.11.22 at 23:58:05(1651) Aerial roots. The use and purpose of aerial roots could well start an interesting discussion amongst the Aroid-l group. So far only a few comments have been made but widely differing views have been offered as to what should be done with the Philodendron "Xanadu" aerial roots. We've grown Philodendron's in a garden setting for many years mainly with the help of three metre iron bark stakes or where there is room attached to trees. At one stage we had twenty odd different plants growing up a single pine tree which in itself give an indication as to the versatility of Philodendron's as pine trees aren't the greatest of trees to grow anything on. (Resin ect.) Aerial roots appear to serve a number of different purposes the most obvious being to attach the trunk of the plant to whatever support it's growing on. (perhaps these shouldn't be called aerial roots ?? ) On the larger (taller) multi stemmed plants masses of roots overlap each other growing into any crevice that can be found making the plant pretty hard to remove. Other aerial roots from higher up on the plant seem to develop as the plant grows. We have had some metres long, hanging free (from the tops of trees) and as thick as your little finger. These seem to serve only one purpose and that is to supply nutrient to the higher parts of the plant. Eventually they always reach the ground and develop very large root systems, larger then the original plants root system and can spread out over\under a large area of ground. I've no doubt that these aerial roots eventually take over the roll of "feeding" all of the plant. Often with the more mature Philodendron's we find the bottom 40cm. of the trunk has rotted away and the only contact the plant has with the ground is through it's aerial roots. +More Other thoughts. As the plant grows the trunk is usually much thicker at the top then at the base, plus it has much larger leaves (depending), perhaps there isn't enough room (bottle neck) to supply the necessary amount of "food" through the original trunk and root systems hence the development of a supplementary feeding system. Back to the P. "Xanadu" aerial roots question. Without any hesitation I would leave the lower roots alone, redirect the middle roots into the potting media and leave the higher roots to develop as they will. Eventually they will grow down into the media and nearly always into another plants pot or territory. If you feel like experimenting a little next summer with one of your "Xanadu's" that has aerial roots, wack off all the leaves down one side, unpot the plant and lay it on it's leafless side in a shady part of the garden placing the odd aerial root into the ground. Go back at the end of summer, dig up the roots and see for yourself what has happened. Peter. 

From: Sue Haffner <sue_haffner at csufresno.edu> on 1997.11.25 at 00:07:13(1658) Thanks to all who commented on aerial roots and how they should be treated. I divided and repotted this plant over the weekend. There are now 3 'Xanadus'; each had one aerial root, and most of them were at least 15 feet long! I wound the aerials around the base of each plant and repotted them, with the aerials mostly resting on the soil surface. +More I'll let you know if anything else happens. Sue Haffner

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