Snails (from an old
native plant website)
Snails are not found on the strongly mycorrhizal plants (95% of West Coast USA native plants). The highly mycorrhizal (VAM) plants are eaten only if the plant has lost, or disconnected from the mycorrhiza. The snails live on the weedy plant species that are poorly mycorrhizal or non-mycorrhizal. Native snails live on the dropped leaves in the litter, not on the plants. Coastal towns are knee deep in European snails that are living on the 'color' plants (basically weeds) people set out in their gardens, and additionally overwater and fertilize.
Mycorrhiza
The best disease resistance for a plant is to become mycorrhizal. The
root system of a West Coast USA native plant can grow 3-5 feet per year and the mycorrhizae about the same. Water-stressed plants can have a huge root system after a year, and be 'locked' into the same mycorrhizal grid as the
trees around them, giving access to a wealth of nutrition and moisture.
When the plant's
roots mesh with those of its companion plants, the growth can be amazing! The plants can stop spending all their
energy growing roots and can spend energy reproducing (flowering) or protecting themselves. Again, the more early watering, the harder it is to establish the plants onto the grid. If you
water so the top part of the root ball is allowed to dry out between watering this encourages the plant to make mycorrhizal connections. If a native drought tolerant plant stays wet it will not become mycorrhizal.
Also, if the plant dries out too much as it is trying to become established, it will again exclude the fungus because it does not have the 20% energy reserves to commit to the mycorrhizae.
The same situation occurs if you apply the wrong mulch. Also weeds are negative to oaks as weeds commonly abhor mycorrhizea and either draw from it or compete with it.
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An important distinction: Permaculture is not the same kind of gardening as organic gardening.
Mediterranean climate hugel trenches, fabuluous clay soil high in nutrients, self-watering containers with hugel layers, keyhole composting with low hugel raised beds, thick Back to Eden Wood chips mulch (distinguished from Bark chips), using as many native plants as possible....all drought tolerant.