There are several other ways to get Dragonfruit. First, you can fish for them at the pier in Magnolia Promenade, very reliable in my experience. Your Sims could also fish in Magnolia Blossom park way in the back. There are three spots, the middle one was where my Sims get them. Not as reliable as Magnolia Promenade though. If you have the ROM pack, your Sims can buy them from one of the vendor stalls in Caster's Alley. Lastly, if they're high enough in gardening skills, they can get a Dragonfruit by taking a cutting from a strawberry plant and grafting it to a snapdragon plant, or vice versa. Hope this is helpful!
Happy Simming! <3