it takes about 1-3 days to grow
Wild blackberries that grow in lightly wooded areas, although if allowed I am sure they would take over the lawn too. The berries are small, but sweet and certainly edible.
There are several different tiers of berries. Berries such as the chesto berry take a relatively short amount of time to grow; maybe a day. Mid-tier berries such as the rabuta berry may take a bit longer than that depending on how often you watered it. However, top tier berries such as the pamtre berry takes 72 hours to fully develop.
however long it takes, god!
Actually it depends how how much you care for it and for what type of berry it is.
4 weeks
Once you have the Berry Grow thing, you can plant the Oran Berries into it. It may take awhile though, like a couple of hours.
about 6 months
the berries take the water
If you have just planted one it will take four days for it to grow ( be sure to water it every day and you may receive extra berries! ).
First you planta lot of long grass. Make sure that your garden is not to full. Then plant a few black berry bushes. It will take a while for them to grow, so be patient. If your having trouble with this, you can buy black berries from the store. If your berries go rotten get rid of them! This won't help persuade the Doenut coming to your garden. Keep checking your black berry bushes (Y) and when they have fruit on them, use your spade to tap (X) the bush and berries will come off! Now you have to wait for the Doenut to come. REMEMBER Remember to have lots of long grass and space in your garden.
My sources say about 12 hours. Although I am not sure. It is in regards to heart gold . I think it is the same though.