Sort of. I am a complete novice gardener, only started taking an interest for the first time ever (I am 42) a couple of months ago. We have a very established garden, full of mature shrubs (all planted by the previous owners), but we've neglected it for way too long and as a result everything is very overgrown and woody and we are completely swamped by weeds.
I cannot afford to replace established shrubs really, so I can only 'theme' what I buy going forwards. So any perennials or flowering shrubs that I buy have to be white, pink or purple. I like non flowering shrubs too, but I wouldn't buy anything yellow, orange or red. Its not that I don't like them, I really do like seeing them in other gardens. I just prefer the calmer colours, and it helps me to think a bit more clearly when choosing.
Recently, I've bought two pink roses, a pink peony, a white camellia, pink escallonia, a pink and a white weigela, lots of verbena, lots of purple tinged hebes, lots white and pink and lots of purple lavender, erysimum bowles mauve, two cistus, a limey cornus, white and purple lilacs, pink ceanothus, magnolia, fuschia hawkhead and delta's sara, three different mophead white hydrangeas, lots of heucheras and hellebores and some shrubs with pink tinged foliage - red robin Louise and pittosporum Elizabeth. And I've also bought polemonium and a huge amount of salvias. Plus some plants for pots, but I am fussy about bedding plants so I've just bought some purple and white osteospernum, white alyssum, white and pink bacopa and some pale pink geraniums, purple salvias of varying heights, purple campanula and white begonia.
Having a bit of a theme has focused me a bit, as I am very impulsive and when farced with such a variety at the garden centre, I just put everything on the trolley! I also have a list of shrubs and perennials that I've either already bought and are on their way, or I want to buy for next year - rhododendron hatzsu girl, deutzia mont rose or yuki cherry blossom, loropetalum chinese var rubrum Fire Dance, daphne x transatlantica Eternal Fragrance, black elder Black Beauty, a snowball tree (I think it is a variety of viburnum) and a lily of the valley shrub Pink Passion. So having a sort of theme has helped me hugely in that as now I know what I will buy and can plan ahead. And on a smaller scale, I will be buying lupin and allium bulbs this Autumn rather than buying them next Spring when they will be much more expensive.