In Chapter One the Simon, Jack, and Ralph go on their first expedition. It is Simon who first recognizes and identifies the candle buds. Ralph is not interested. He dismisses them by saying "They can't be lit. Jack "slashed at one with his knife," and also is not interested. If the boys can't eat them, he has not use for them. We see early on how each boy responds to nature, telling us much about each boy's personality. Jack is interested in food, immediate gratification, and is antagonistic toward nature. Ralph is the practical one, interested in what can be used; Simon enjoys the beauty and serenity of nature. He enjoys nature for nature's sake.
When I read about the candle buds in chapter three, as Simon retreats into his sanctuary, I think they stand for a couple things simultaneously. To Simon, they appear to be something of a calming influence, the "riotous colors died and the heat and urgency cooled away" as they open up and he retires by himself to his quiet place in the woods.
But to the rest of the boys, they may in fact symbolize the coming terrors of the night as they spill out "their scent and [take] possession of the island. The rest of the boys are absolutely terrified of the night and flock together in order to try and stave off the horror of it.
So in my mind at least, the candle buds stand for both things, at least at this point in the novel. When Jack attacks them later, perhaps other symbols could be found there as well.
I agree with response #1 however, what is your evidence that suggests Simon is venturing to his spot to pray?
Also, the candle buds could reflect Simon's personality. He ulitmately has a 'wall' however, in certain conditions, he 'opens up', and pure goodness and delight spills out, overtaking and overpowering some of the darkness.
This section of text (chapter 3) is preceded with Jack's animal-like behaviour in the jungle.
The closing scene of the chapter is Simon's. Much like Jack, he goes alone and unafraid into the jungle. Although the harshness of the jungle environment unfolds through Jack's eyes, there is still beauty,
"With the fading of the light the riotous colors died and the heat and urgency cooled away. The candlebuds stirred. Their green sepals drew back a little and the white tips of the flowers rose delicately."
Simon loves nature, and the description here is filled with a sense of awe for it. Simon is the Christ figure who goes into the wilderness to pray, and the jungle shows him its undetected beauty. Butterflies often follow him. The beautiful candle-buds, seen through Simon's eyes, is just one of many beautiful images that Simon sees in his world. It is interesting that Golding always softens his language of landscape and nature when seen through Simon's eyes.