1 Tbs Potassium permanganate to 2 gallons water in a bucket. Make sure to rinse with plain water before putting in the pond. This can be purchased from repair places for water softeners.

They said that bleach will kill the roots. So that should not be used.

If you put them in the pond without doing this their is a lot of bacteria and parasites that can kill your fish if you just put them in your pond.

This will bump off most nasties with the exception of invasive seeds, larval pests or pests embedded in the plants.

Plants (which may or may not carry eggs, larvae) from the wild, or iffy ponds may carry and transmit khv (devastates koi) Various fish parasites and disease (varying levels of distress up to death) crown rot (devastates hybrid waterlilies) leeches (fairly disgusting when they get between your toes and start sucking) among other things

As folks have said, watch out that you do not introduce parasites into your pond. Snails are usually OK. I suspect my fish eat them because they only seem to survive in the pre-filter and biofilter. I find very few on the plants.

PP will get rid of most single celled bacteria and parasites. You can also dose with Quick Cure to get rid of multi-celled parasites. Something called had a snail will kill the snails. Make sure all this dosing happens in a quarantine container.

All plants can be infected with parasites. I don't see a difference between the potential hazards of plants from the store or plants from the wild. At least I know the where the wild plants came from.

For the most part, plants from local lakes are native to the region and plants from the store are the invasive species.

You might think isolating them is good for reducing the risk of pests or parasites, only to find they drop thousands of seed that spring up in every nook or cranny and plant pot...

A feature of the 'cultivated' varieties and those found in collections is while they have some redeeming features by way of looking nice or doing something useful in season, their growing habits are known to be fairly easy to control

While there are some risks associated with circulating plants from other folks collections, when you know what you are planting you stand a much better chance of growing something which is likely to be a long term asset rather than a liability

I never had a wild plant that caused any growth or invasion problems. I can't say the same about some of the store plants I experimented with.

Somehow it comes as no surprise some stores put iffy plants from iffy ponds on shelves with thoroughly inadequate descriptions, just as some resellers have no problem fobbing off crown rot infected plants, boxed blue hardy waterlilies bought from China at 5c apiece or dangle some mundane run of the mill fickle flimsy tropical waterlily for as much as $20

Fortunately theres no need to be stuck with iffy plants from iffy ponds or skallywags when specialist collectors provide a better choice at a better price on EBAY :)