Chicken poo good, can't really go off
Feed all plants in pots with weak (1/2 strength) tomato feed every week when growing. Tomato feed good for just about everything( including grapes,) as all fertilisers have basicaly same ingredients but in varying proportions. By limiting yourself to one, i.e. Tom. fert., you can buy large bottles/packs more economically. Can't go very wrong.
Woodash good but not too close to plant or might "burn"
Acers can lose leaves to wind burn. They can dry out quickly as they have very thin leaves.
Potash can be bought in garden centres. Again tom.fert. high in potash
Plant camellias any time, preferably in acid soil or ericaceous compost if in pots. if you haven't got acid soil the latter may be best. Water mainly with rainwater. Keep nice and moist/wet in autumn as this will encourage flower bud formation for spring flowering. Feed with special camellia food, and twice a year dose with Iron Sequestrene to encourage take up of food.
Dilute nettle juice 10 to 1 with water.
If any of the above is incorrect others should add or correct it please