I'm against the idea just because blueberries and chantrelles are some of the few things a newbie can use as a trade good. Being able to cultivate them would just make it so you could hide in your walls and farm what you need, remove any potential trade demand for the item (and low level trading needs to be much more encouraged in game, it's already so limited).
Being able to cultivate foragables would just increase the monopoly established factions and settlements have over hermits, nomads, and newbies. And already the ease of resource monopolization is a major problem with the hearthlands as it is, with a static world size.
Edit: also, I already have a "blueberry farm": I have barter stand selling processed food and basic items for blueberries and chantrelles.

Hearthlings: Marona; Chamberlain (retainer alt), Vincavec (shaman of the Dryad Wells Forest)