You will find berries and trees seedlings avaible at Daisy's Flowers. Tree's seedlings cost from 600 to 980 ritch, as prizes vary daily. Berry's seedlings always cost 100 ritch; to buy them, talk to Daisy and select the option "Buy berries".
Planting Tree's Seedlings
Trees take two days to grow. In order to get tree's seedlings to sprout, you might want to plant trees in this fashion:
X = blank space, F = flower and S = seedling
In order to get tree's seedlings to sprout with a better percent you'll need to place flowers around the seedling. Note that trees seedlings might not always sprout, and that it might take two tries in the same spot around the flowers to work.
In addition to normal seedlings, those that have round leaves, there are spiky-leaved ones that turn into pine trees, these are exceptionally hard to grow. If you wish to grow Forest Trees you must plant normal round seedlings in the forest and they'll become forest trees.
Trees also can't grow very close one to another; and they can't grow right beside a house, bridge, stairs, etc.
Trees live around 30 days, and after just start withering and die, once dead they leave a sapling in their stead. Spiky-leaved trees live for shorter amounts of time.
Planting Berry Bushes
Berry bushes take one day to appear, and three days to bear berries. If you plan on growing them in your town you might want to plant them in this fashion:
X = blank space, F = flower and B = berry seedling
In order to improve the rate of growing berry bushes you will need to plant them in such manner. It seems this is a very accurate way, as in my town all berry bushes had sprouted.
Berry bushes last around 3-5 days. Once you pick the berries on it, the bush won't grow any more berries and will die after 3 days. Berries turn rotten a day after they're picked if they're left in your inventory. In order to preserve them keep them in your drawers in your dorm room.
That's all you need to grow your berries and trees, now happy planting!