As per shastras, lighting a diya before 4 plants brings in good luck

The Vedas, Puranas, the Upanishads, and more, are the knowledge-giving books that every Hindu looks up to and reads for their knowledge and wisdom. They talk about the divine, the nature of man, the duties of humans, the Gods and their characteristics, the power and importance of nature, and much more.
And with time, the ancient scriptures and Shastras are seeing a revival with more and more people being interested in studying them and changing their way of life or improving their everyday practices.

The Peepal tree is one of the most worshipped trees in Hinduism and is believed to be the abode of the Gods. In fact, in the Bhagwad Gita, Chapter 10, Verse 26, Lord Krishna says “अश्वत्थ: सर्ववृक्षाणां” which means ‘Among trees I am the Ashvattha (peepal tree).
And it is thus believed that lighting a diya before a Peepal tree, especially on a Saturday, helps remove certain doshas from life. And while the diya for other plants is lit up with Ghee, for the Peepal tree, people prefer a diya with mustard oil. It is said to help in removing negative energies, invite positivity into the person’s life, and much more.

The Tulsi plant is one of the most respected plants for Hindus around the world, and is worshipped not just for its medicinal properties but also its symbolism. It is said that the Tulsi plant is an incarnation of Maa Lakshmi, the goddess of wealth and purity, and having a healthy Tulsi plant at home ensures that the family remains healthy, happy, and abundant.
It is said that keeping a Tulsi plant at home, watering it, and lighting a Diya near it during the evening or morning time purifies the atmosphere at home, removes financial problems, and brings peace in the family.
And so people light a Ghee lamp near the Tulsi plant and worship it.

The Shami tree is also considered sacred in Hinduism and is often linked to Lord Ram. It is said that when Lord Ram, Lakshman, and Mata Sita were in ‘Vanvaas’, they often took shade under the Shami tree and also worshipped it. It is also believed that the Pandavas hid their weapons inside a Shami tree during their exile.
And so, it is said that lighting a diya near the Shami tree can be very beneficial for people. It gives people protection in life, helps them reduce the negative effects of certain planets, and also overcome obstacles in life.

The banana tree is often called the tree of prosperity, and people also light a diya near the Banana tree in the early morning. The tree is considered sacred and its leaves and fruit are used in religious rituals too.
And people light a diya near the Banana tree for blessings of prosperity, happy relationships, fertility, and the likes. It is said to be a symbol of Lord Vishnu and Maa Lakshmi, and thus, married couples worship the tree.
It is also said that worshipping the tree on a Thursday or lighting a diya near it brings wisdom and wealth in life.