Dave
PIP-- I envy your green thumb. I'm currently in the process of killing both a bamboo plant and a norfolk pine, apparently both pretty hardy houseplants.
its mostly attributed to ocd, patience, and an inert sense of balance. read about what you are growing, every asprct must be considered , you dave, are mother nature! wow huh?
i bet your bamboo should be fed a very very light vegetative nutrient( (N2 P1 K1) 1/3 strength once a month for the nutrients and watered with a neutral ph.
your evergreen, though would like a ph of 5.9-6.5 the same ferts, but more often or at a grater strength, i am certain the evergreen wont take much watering, let the soil dry out before watering again, you are most likely over watering, that is the most common problem, i catch my self tring too often, but its more patience involved to add to your character and plants health!
read read study study!
i love talking about growing anything, so pm me if you have any other Q's, maybe i can answer or point you towards someone who can.
is a necessity, especially for plants such as yours. they have a full line of ferts to apply though out the growth stages. but your plants arent going to flower so a strict vegatative diet will help them, the sea weed and bat guano in that will form microorganisms that bind to and protect your root system from harmful microorganisms. like phagocytes, or an antibiotic.
G/L!