If you want to be sure to keep any plant you should give it away. It’s the gardener’s reinsurance policy. Give it, of course, to someone with green fingers who can give it, cutting or seed, back if you then lose it.
I reinsured a lovely white-flowering form of Honesty, doling out its seed to anyone who admired it. When it flowered in conjunction with its transparent seed-capsules it lit up its corner. Where is it now?