[Paul Plots]

So what's this paste that you seal the wounds with?  Can I make it, or do you buy it?

I think you buy it... I'm sure I've come across it in a hardware store... it acts as a seal.

Years ago people probably either made their own or used some substance that acted like a sticky / waxy seal.

[Trillium]

Over here it went under generic names like pruning paste or pruning paint. Ours was a spray form and it came out black, probably a tar base that sealed off the wound. Don't see it much now as the 'experts' say it's better to let the branches scar on their own.