i'v heard of people sowing a few bagseed in the garden and had it grow into a fullon bush but i think its hihly unlikely it was all that big.

ground is a huge factor and if you get some worm castings or manure (chicken is the best) and mix it up with your soil then ad some quick lime to the soil but be carefull to keep the ph round 6.5 (use viniger to lower ph)

the lime loosens the soil whilst ading calcieum.

all the bigest mistakes i'v seen have been from when people have fidled with nutrients and stuf without several years experience with a sucsesfull plan.

start basic work up