Out of diagonal, horizontal or vertical, which works best for you in New Leaf? I decided to dedicate today to getting my hybrid garden started, & I could use the best tips you have!
--Plant your breeding flowers in a "W" formation...
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--Only water the flowers you want to breed! (If villagers water random flowers, don't worry. It doesn't affect breeding.)
--Planting fertilizer adjacent to your breeding flowers does help, but I don't think it's a guarantee.
--You know how villagers randomly plant flowers wherever they go? Sometimes when they do that, it can override an existing flower. (I think it's a glitch, but I have seen it happen and have seen others mention it, too.) To prevent this from happening to your hybrids, consider building the fence PWP to plant your most important breeding flowers in. In my experience, villagers don't mess with them while they're in there.
I've never had much luck with breeding flowers that I placed horizontally or vertically, without the "W."
Oh, yes, Jacob's ladders. I use those sometimes in place of fertilizer, but I can't tell if they actually help. Supposedly they do, so I still try. They certainly don't hurt.
I plant mine side by side in a border around town. They can't be destroyed by anyone moving in, and I have a ton of hybrids now. I also plant them around pwps and villager's houses, but those don't grow as often as the ones in the border. I plant my excess hybrids on the beach, also side by side, and they breed fairy often.