Fill every cell with either a Tree or a Flower.
Each row and each column must contain the required number of each plant. On an even-sized board of side N, that is exactly N / 2 Trees and N / 2 Flowers; on an odd-sized board there is one more Tree than Flower.
Three identical plants may not be consecutive horizontally or vertically. A run is any three adjacent cells in one row or column; diagonal cells do not count.
No two completed rows may have the same Tree/Flower arrangement. No two completed columns may have the same arrangement. A row or column is compared only after every cell in it is a confirmed Tree or Flower; notes and unknowns do not participate.
The puzzle is solved only when every cell is confirmed and all four rules hold. Each published puzzle must have exactly one valid completed grid.
Two identical plants side by side would make a run of three if a third joined them, so the cells immediately before and after the pair must both hold the other plant.
Example: A row reads 🌳🌳 with an empty cell on each side. Both of those cells are Flowers.
Two identical plants with a single gap between them cannot be completed by a third of their own kind — the gap would close a run of three.
Example: A column reads 🌷 · 🌷 with one empty cell in the middle. That middle cell is a Tree.
Once a line already holds all the Trees it is allowed, every remaining cell in that line is a Flower — and the same the other way round. The badge beside each line counts both plants for you.
Example: On an 8×8 board a row already shows four Trees. Fill each of its remaining cells with a Flower.
Count what a line still needs against how many cells it has left. When the numbers match exactly, every one of those cells is decided at once.
Example: A row needs three more Flowers and has exactly three empty cells. All three are Flowers.
A completed line rules its arrangement out for every other line of the same direction. When another line differs from it in only one undecided cell, that cell must take the value that makes the two differ.
Example: Row 2 is finished. Row 5 matches it everywhere except one empty cell, and that cell would be a Tree in row 2 — so in row 5 it is a Flower.
Two lines that are still incomplete but already identical everywhere they are filled will have to differ somewhere. Look for the position where only one of them still has freedom.
Example: Two columns share every filled cell. One of them has two cells left and the other only one; the single free cell is where the difference has to land.
Every plant you place sits on one row and one column at once. After finishing a row, walk down each column it touched — a quota or a pair often completes there immediately.
Example: Filling a row’s last two Trees may push a column to its Tree quota, which then turns that whole column into Flowers.
The gutter badge for each line shows Trees over Flowers against their targets. Neutral means still open, green means the line is done, red means something in it already breaks a rule.
Example: A row badge turns red the moment it holds one Tree too many — undo back to where the extra one went in rather than hunting the whole board.