The Oak Tree is the largest and most expensive tree to grow.
The oak tree needs to be fertilized with Green Fertilizer at 3 to 4 hour intervals, beginning with the 2nd growth burst, which takes place between 6 and 8 hours after planting, depending on the time of day you plant. The oak tree has 5 growth bursts, the first and last of which you cannot fertilize. The period of fertilization with the oak tree lasts from the appearance of green buds at the tips of the branches until the disappearance of the falling leaves that burst from those buds. The entire tree takes about 17 hours to grow fully. The oak tree will attract Eaglairs too.
Costolot's Store will only sell Oak Trees starting at Gardener Level 36 to get an Oak Tree, but Oak Tree seeds can be obtained from the Mine at a lower level.
Apple Tree · Banana Tree · Bird of Paradise · Blackberry bush · Bluebell · Bullrush · Buttercup · Carrot · Chili · Corn · Daisy · Fir Tree · Gem Tree · Gooseberry bush · Hazel Tree · Monkeynut Tree · Nightshade bush · Oak Tree · Orchid · Poison Ivy · Poppy · Pumpkin · Snapdragon · Sunflower · Thistle · Toadstool · Tulip · Turnip · Venus Piñata Trap · Water Lily · Watercress