Leif will visit your town around once a week to sell rare flower seeds and shrubs! He sells flower seeds that you can’t find at Nook’s Cranny. The seeds he’ll have on offer will be different for everyone depending on what their native flowers are and what Nook’s Cranny usually sells on their island.
You can also sell weeds to Leif for double the usual price! Timmy and Tommy buy weeds for 10 bells a piece, but Leif loves weeds so much he offers 20 bells each weed! You can sell as many weeds as you like to him.
If you aren’t playing during Nature Week, then Leif will give you the Hedge recipe instead of Nook. To get Leif to gift you the recipe, you must have had him visit a couple of times and bought lots of bushes from him. The exact number is random, but a minimum of 20 should be bought. To make 10 hedges, you need 2 stone pieces, 5 tree branches and 10 weeds.