What is the significance of flowers in Hinduism?
Why are temple decorated with flowers and why are Gods pleased with flowers?
The explanations are given in the context of Devi Puja but readily can be applied to other Deities as well.
For Pushpam(flowers), which is one of the Pancha as well as Shodasa Upacharas,the following explanation is given:
- Pushpam – Offering flowers and doing pooja.
Sutra 38. “Ahimsa prathama pushpam, pushpamindriyanigraha dayakshmagyanapushpam panchapushpam tatahpara”
Ahimsa or non violence, indriya nigraha or control over the senses, daya or kindness, kshama or forgiveness and gyana or knowledge are called the pancha pushpas or five flowers with which we can control our ahamkara or ego and surrender to God. Hence worshiping the Deity with flowers is symbolic of controlling these and surrendering to God
So someone,who practices Ahimsa,Indriya nigraha,Daya,Kshama & Knowledge.is already worshiping God with 5 flowers even if he is not actually doing ritualistic worship.
However, what Nithin said(in comment) is also technically correct :
Flowers denote Akasha Tattva in the Panchopachara offerings given to deities. – Nithin Sridhar
Offering flowers is said to satisfy the Akasha(Ether) Tatva(element) aspect of the Deity.
The correlations of the Pancha Upacharas with the Pancha Tatvas are as follows:
oṁ laṁ pṛthivy-ātmane gandhaṁ parikalpayāmi | I offer scent in the form of the element earth.
oṁ haṁ ākāś-ātmane puṣpaṁ parikalpayāmi | I offer flowers in the form of the element ether.
oṁ yaṁ vāyur-ātmane dhūpaṁ parikalpayāmi | I offer incense in the form of the element wind.
oṁ raṁ tejātmane dīpaṁ parikalpayāmi | I offer light in the form of the element fire.
oṁ vaṁ amṛtātmane neivedyaṁ parikalpayāmi | I offer food in the form of the element water.
oṁ saṁ sarvātmane tāmbūlaṁ parikalpayāmi | I offer betel in the form of the entire Universe.
The Kularnava Tantra gives yet another symbolic explanation of the term "PUSPA" :
Puspa: Because it increases merit, punya, removes the heap of sin, papa, yield much wealth , puskalartha, it is called puspa.
As regards decorating temples with flowers ,i don't think there are any other significance of it besides decorating the temple & making it look good.
Just as we decorate our own rooms and houses with flower to increase the aesthetic aspect.Similarly here,Also flowers emit fragrance.