Last week was pretty heavy on the theory, so I thought I'd stay with the ideas of saturation and value this week, and demonstrate some ways to play with them, using the crocus palette as a starting point.
The first thing you could do with a Nature-derived palette is to work with it exactly as you find it.
This is the challenge I set myself for the Patterns in Nature series, mainly because I wanted to break out of my colour comfort zone and learn from what I found rather than judging it. It is by no means the only option, and once you take the step of translating a pattern into yarn, you will be forced to make choices and compromises in any case. It helps immensely to know which changes will be most likely to yield the outcome you have in mind.
Starting with the, ahem.... exuberant option:
ie.
Nudging the warmest and coolest hues into direct opposition on the colour wheel, choosing a dark, saturated version of purple and a light, saturated version of yellow-orange (in equal amounts, to boot) yields just about the maximal contrast you could ever hope to achieve. Fabulous for a 7 year old's birthday cake, possibly less so for all but the most extroverted fashionistas.
What if you liked the cheerfulness of the contrast, but wanted to tone down the eyeball searing effect a wee bit? One option would be to maintain the contrast in value (dark/light) but go for less saturated versions. Changing the proportions would further civilize the combination.
You could reduce the difference in value but maintain the saturation:
Or some combination thereof - playing with value and saturation gives you loads of options for fine-tuning the dramatic effect of a palette. Don't forget that the characteristics of the fibre itself will also affect the optical result - texture, fuzziness, and shine all create effects that alter the perceived properties of a colour. (More on that another day.)
At the opposite (but much more common) extreme: what if you are terribly conservative about the colours you wear, but fell in love with the royal velvet of that crocus? You could fall back on the safe option of simply combining lighter and darker shades of purple, but the result (though attractive) lacks some of the depth and complexity that made the original so appealing. You might like to benefit from the added spark of a complement, nevertheless, it will be a chilly day in Hades before you wear orange.
One solution is to tame the complementary colour until its origins are so subtle as to be barely recognizable. There are a number of ways to achieve this, such as adding orange to the purple to progressively desaturate it to a nice unassuming brown, or vice versa. (This is where an accurately printed colour chart comes in handy, but I will try for a reasonable approximation here.)
Another solution is to go back to the original three-way palette (top of this post), but keep the proportions severely in check.

A tweedy yarn with infintesimal flecks of the desired colours can be particularly helpful in this regard. Placing the warm hues within areas of similar value will also help to keep the contrast in check.
The possibilities are infinite. The general principle is that drama is heightened with increased saturation, wider contrast (light/dark, warm/cool) and large blocks of the contrasting colours. If you love a particular palette but are uncomfortable with the dramatic effect, try isolating the aspects that most appeal to you (eg. richly saturated dark purple) and tweak the remaining colours to fit your personal vision.
Fine tuning the contrast in this way comes in particularly handy when planning traditional Fair Isle - but that's a topic for another day.