Survival: Roof (Hard) - Melons and Gloom-shrooms

This strategy uses Winter Melons to do heavy damage and freeze groups of zombies. The Gloom-shrooms are to heavily damage the nearby zombies faster.

1st round (Flags 1-2)
Start planting Sunflowers and use Potato Mine for the first zombies until you have Gloom-shrooms. Later plant Gloom-shrooms in Pumpkins at column 6 and Umbrella Leaves at column 5, rows 2&4 to stop the Bungees. Upgrade Sunflowers at colums 2 and 5, rows 1,3,5 to Twin Sunflowers.

S - Sunflower

T - Twin Sunflower

G - Gloom-shroom

U - Umbrella Leaf

- Pumpkin

2nd round (Flags 3-4)
Replace Sunflowers in columns 3&4 with Melon-pults and upgrade one in each lane to Winter Melons. Place Umbrella Leaves at column 2, rows 2&4 for Bungees and Catapults.

M - Melon-pult

W - Winter Melon

3rd round (Flags 5-6)
Add more Melon-pults and upgrade them to Winter Melons.

4th round (Flags 7-8)
Continue adding and upgrading melons.

5th round (Flags 9-10)
Replace some Twin Sunflowers with Melon-pults for Zombonies and Gargantuars but keep at least 3 of them. Also pumpkin the Winter Melons for the Imps. If there are no Bungees, replace Umbrella Leaves with Melons.

Variations
Another column of Melon-pults can be added at column 6 while the Gloom-shrooms are at column 7. In the final round, replace the Umbrella Leaves if there are no Bungees and 3 Twin Sunflowers with Melons.