Pests Are Inevitable

Asian  Tramp Snails -  Bradybaena spp.

One can believe in the tenet of letting nature take its course, but the harsh reality is that no matter how much we try to landscape naturally, our landscapes are not fully natural. In nature, the presence of these garden snails would be part of a bigger picture and part of a natural balance. In my emerging landscape, these snails are multiplying like crazy and mowing down the seedlings I'm attempting to grow in my hobby nursery - Hawthorn Hill.  For several weeks after I first spotted a few, I left them alone, but I began noticing that many of my new seedlings were disappearing or being mowed down to the dirt line. Leaving the snails alone was starting to cost me dozens of seedling wildflowers. If one were to watch these snails, you'd notice that they were primarily feeding on the dead/decaying leaves in each pot, but they didn't confine themselves to this diet. Removing the dead vegetation more judiciously didn't help. It simply made them hungrier for the vegetation that remained.
I do not believe in needlessly killing the things that appear as pests, but sometimes the pests give us little recourse. Native plant landscape or not, land management is a requirement for any landscape that we artificially put together. We just have to be wise in how we manage. A widespread use of pesticides, for example, is NEVER the answer to a pest problem. Pesticides do not select to work on the "bad actors" while leaving the "good guys" alone. They kill everything and in doing so upset any balance of nature that might eventually develop without our intervention.

Aphids feasting on the new growth of my cockspur haw

Aphids are the classic example of this. There is no doubt that aphids suck the sap of the new growth of many of your plants. In doing so, they can cause a great deal (mostly temporary) of damage. Plants, however, advertise the presence of aphids when they are under attack and this brings in the aphid predators - ladybug beetles and lacewings. Sometimes, it takes a week or more for these aphid predators to appear, but they always do IF the landscape is not being routinely sprayed with pesticides. Once they find your aphids, they will remain, lay eggs and multiply to the extent of your aphid population.
But, back to my snails... I cannot allow these pests to consume my plants, but I can hardly condemn them to death because they are doing as nature intended, so each evening around dusk and each evening right after sunrise, I patrol my plants and collect all the snails I can find. I often find a dozen or more. My backyard is surrounded by a 6-foot privacy fence and the lot behind me is vacant, so I use my former baseball prowess to throw them as far over the fence as I can.  I figure that if they can find a way to return, I will throw them again, but I expect they will find plenty of decaying vegetation in the vacant lot.
Land management is a never ending pursuit whether we manage a multi-thousand-acre nature preserve or a 1/4-acre lot in suburbia like I currently have. Simply use the management method that fits the needs of your landscape.