Xisca, good point and I am not 100% sure of
the answer. My
PDC teacher made this claim and I did send him an email to clarify. This website might explain the statement
http://www.laspilitas.com/advanced/advroots.htm It is mostly about CA
natives, but here is a section where Jacaranda is mentioned.
From the website:
"Ectomycorrhiza is the second type of fungal association.
It is sometimes dominant amongst shrubs and trees in our Mediterranean climate where the rainfall is above 10 inches (30 cm), winter wet, summer dry. The plants that use ectomycorrhizal are under intermediate nutrient stress or seasonal nutrient stress. In our state the winter rains provide a specific bacterial haven for the limited breakdown of the litter in early winter and early spring, providing a small amount of nutrients. The ectomycorrhiza are active in most soils at these times when this nutrition is available to them. They are excellent at extracting the nutrients from the litter as it is being made available. (see Mulches) This litter in the wild may only be one cm. (1/2") thick. That cm. will contain the limiting nutrition for that site and provide the site protection from diseases.
It takes about 6-8 weeks before the ectomycorrhiza become functional on new roots. As ectomycorrhiza become functional they release a chemical (IAA) that encourages rooting (on them, not on other plants). What normally happens in mulched plantings is minimal top growth for a few months to a year after planting, then the plant grows fast. The young plant expends its
energy for the first months on
root growth and mycorrhizal establishment and has not accumulated
enough auxin to stimulate top growth. One Arctostaphylos glandulosa was dug out of the demonstration garden because it was planted in the wrong spot, the roots had grown 1" in 10 days. (the root ball itself
should have ectomycorrhiza present.) Other native plants have been moved after a year (they generally died after transplanting), and the root ball from a gallon plant is normally 3 feet across and deep.
It appears that many of our California plants have the ability to be both ectomycorrhizal and ericoid and/orVA. These plants serve as energy bridges/shunts in an ecosystem. The best examples of this are the oaks, willows, cottonwoods, currants, Rhamnus species, roses etc.. These plants act as bridges between water sources and dry hillside, different soil levels, different plant strategies and between different plant communities."
and:
"Non-native plants that can also be ectomycorrhizal (They might also sometimes be VA and sometimes they are not supported by our mycorrhiza.):
Abies, Cistus, Jacaranda, Picea, Pyrus, Tilia, Acacia, Crataegus, Juniperus, Pinus, Rhododendron, Tristania, Carya Cupressus, Larix, Platanus, Ribes, Tsuga, Cassia, Eucalyptus, Leptospermum, Prunus, Robina, Ulmus, Cedrus, Fagus, Malus, Pseudolarix, Rosa, Vicia, Celtis, Fraxinus, Melaleuca, Pseudotsuga, Sorbus, Vitis, Helianthemum
Generally, if the plant is Ectomycorrhizal or Arbutoid mycorrhizal they need to be mulched for the mycorrhiza to be stable. Arbutoid mycorrhiza is another type of mycorrhiza and only forms on some of the genus Arctostaphylos, Arbutus and a few Rhododendron spp. There is some dispute as to its identity. It may be only a funny ectomycorrhiza. The arbutoid fungi are basidiomycetes and are also called ectendomycorrhiza. We treat it here as ectomycorrhiza as we have found in our installations they are interchangeable as long as we plant by community."
So, maybe that is true for SoCA. Not so much the tree itself, but the associations. I emailed my teacher and asked to clarify......
And the tree will stay, no matter what. It came with the house, is long established and great for shade.......