I planted morning glories last May when all danger of frost was past, just as instructed by those in the gardening know. I watched them struggle in June, and in mid-July they began to grow at a breathtaking pace as the sun and the rains came to encourage them towards rampant maturity. I went on vacation in August and came back expecting to be greeted by seas of heavenly blue flowers. What I saw was a massive tangle of green vines with hardly a bud in sight. I moaned about their lack of satisfaction and gave them up.
In late September, while I wasn't looking, one flower actually came into bloom, and then, a day later, another followed suit. More buds lengthened and showed promise, and a few mornings later, one day away from October, they burst forth in garlands of the blue flowers I love so much. A morning glory flower greeting the sun as it makes its morning ascent has got to be one of the most beautiful sights in the world.
Here is another beautiful morning glory sight: once the flower is spent, drooping and curled after a hard day's work, you can pick the flowers, boil some water, and mix the two together. The blue color dissolves in the water, and like many other colors in flowers and fruits, changes color when an acid or base is added to the blue solution. Add a drop of colorless vinegar - and the blue dye turns pink; a little baking soda, and it turns green. If I add a drop of vinegar to the green solution - it turns back to blue; a little more and - it's pink. These colors are clear and beautiful, and are, in fact, due to the same compound that is in the blue flower, but which takes a slightly different form depending on whether it is in the vicinity of an acid or a base.
What does Dover see when he looks at the fence covered with blue flowers? Dogs do see color, but probably more palely than humans do, and they are also apparently red/green colorblind, like 4% of the male population of humans. So he sees the flowers as pale blue, possibly against a yellowish/gray backdrop of what we call greenery, but what he really sees is the tennis ball on the sidewalk, which is clearly much more desirable than all 37 tennis balls on his side of the fence.