Sometimes it is really hard to please the Head Gardener in the family. This week it was about where to put his Imperata cylindrica 鈥楻ubra鈥� (Japanese blood grass). He has already moved it once in his garden but was not happy with its new location. So, he has been agonizing all week about where to move it next.
He eventually decided on the new spot for the blood grass but had some niggling doubts so he asked for my opinion. (That sure does not happen very often!)
鈥淲ell,鈥� I mused. 鈥淚 can see why you picked this spot because the red grass blades will be a nice compliment to the fall colours on your dwarf fothergilla shrub across the path. But won鈥檛 it be over-powered being so close to your Helenium 鈥楳ardi Gras鈥�? Personally, I think your grass would be better placed on the curve of the bed, a nice distance from the taller 鈥楳ardi Gras鈥� but still across from fothergilla.鈥�
And so ensued a discussion on design combinations between size, form and colour.
John did not like my suggestion because he had given his new Kniphofia 鈥楩lamenco鈥� pride of place in that area and thought the leaf blades on his grass would be too much beside the thin, strappy leaves of 鈥楩lamenco鈥�.
Normally, I would have agreed with him but I suggested the red blades of 鈥楻ubra鈥� would complement the colours of the 鈥楩lamenco鈥� flowers and break up the monotony of the strappy all-green kniphofia leaves through the rest of the season. Not only that, I argued, but the lovely vase-like form of kniphofia would soften the strict, military-like stiffness of the blood grass.
He did mull over my words of wisdom for a little while and then promptly planted his 鈥楻ubra鈥� blood grass where he had already decided to put it. Well, he is entitled to ignore my expert advice because it is his garden, after all, and he is the Master of His Domain. However鈥�
I just had to chuckle quietly to myself a few days later when he announced he didn鈥檛 think he had his blood grass in the right spot. I dutifully kept my mouth shut. There was no need to gloat because now he had the chore of moving his grass yet one more time. Such is the life of a gardener. Always trying to find that perfect plant placement.
Unfortunately, the Duke鈥檚 grumbling did not stop there. The next day he started complaining the fall colours on fothergilla were less than stellar this year. I tried to placate him with the suggestion his shrub may be waiting for a real frost before unfolding in full autumn splendour. And that got me thinking.
Last month I wrote about the science behind fall colours, explaining about the pigments present in the leaves and how the brilliant fall colours develop. What I did not touch on is why autumn colours can be variable from one year to the next and what causes these variations.
You can probably guess it has everything to do with the weather. And boy, can our weather vary from year to year!
We already know the sun鈥檚 declining intensity during the day and increasing hours of darkness are what trigger colour changes. What you might not know is temperature and soil moisture are the main influencers on the vibrancy of the colours. A late spring or a harsh summer drought can delay colour change by a few weeks. And if fall temperatures are higher than usual, autumn colours will be less vibrant.
The perfect recipe for gorgeous autumn colour is warm wet springs, pleasant summer weather and sunny warm fall days accompanied by cool nights. Don鈥檛 we wish.
