Flowers are used as symbolism in this novel. The most important instance of this is the rhododendrons. There is a bewildering profusion of them around the drive leading up to Manderley, and the narrator is startled to see them as she arrives at Manderley for the first time. Indeed they are very striking in appearance, being blood-red and huge. The narrator, in fact, is quite shocked by the sight of them.
These were monsters, rearing to the sky, massed like a battalion, too beautiful I thought, too powerful; they were not like plants at all. (chapter 7)
The narrator, then, finds these rhododendrons quite unnatural, and she feels uncomfortable with them. They are too big, and overwhelming; they seem to actively threaten her, as emphasised by their comparison to a ‘battalion’.
The rhododendrons symbolise Rebecca. They represent her dominant personality, her vividness, her love of life and her beauty. Their unnatural aspect also symbolises her cruelty and depravity, and their lurid blood-red colour hints at her violent end.
The rhododendrons are also prominent inside the house, in the morning room, which again is appropriate as this was a room that Rebecca used a great deal. The narrator feels like an intruder when she first goes in there and sees Rebecca’s desk and all the signs of the businesslike and forceful way in which she managed the affairs of Manderley. The narrator feels totally inept in comparison.
The rhododendrons can also be contrasted with other flowers at Manderley, most notably the tidy, orderly rose garden which can be taken to represent a more homely and virtuous kind of woman, such as Maxim’s mother. Maxim has fond memories of roaming about in the rose garden with his mother when he was a little boy.