The Peepal tree which is called Ashvattha in sanskrit should get married to Neem tree. Both of them are generally grown together or in some cases it is a coincidence that a neem tree raises where exactly the Peepal tree grows.
They consider Peepal tree as male while Neem is female and Peepal tree must be elder to Neem tree. This marriage is to be conducted on Suklapaksha (waxing moon) during utharayana period (January 15th to June 15th). Even in suklapaksha, one needs to avoid first, fourth, eighth and ninth phases of moon.
Those days our ancestors advised that married woman who are infertile to go to this scared trees and offer prayers by walking around the tree for few times a day. There is a scientific reason behind this. We know that some trees produces fragrance in certain season and most of the trees are good sources of oxygen during day time when they are exposed to sun. Some tree products and plants have medical properties. When Peepal tree and neem tree are together they produce a magnetic field. This field along with pure air and focused minds influences the body tissue and organs which could simulate Follicle Stimulating and Luteinizing Hormones and one such missing factor helps in the reproductive process.
Scientific Research has revealed that among trees, Peepal tree is the only tree which produces oxygen in abundant quantity day and night. Sound and interacting flow of wind, with peepal tree, slowly but surely kills infection bacteria as well. According to the book of ayurveda peepal tree leaf, bark and fruit are killers of diseases. Peepal tree leaf has both sweet and bitter taste and has a cooling property. Licking honey placed on peepal tree leaf is believed to cure speech irregularities. Its bark yields tannin which is used in treating leather. Its leaves, when heated in ghee (clarified butter), is used in curing wounds. Ingesting the bark, fruit and buds with different combination of things cure diseases related to phlegm, bile, inflammation swelling and indisposition etc. The soft barks and buds of the tree cure “Prameha”(a disease in which sperms emanate through urine). The powered form of the fruit increases appetite and also cures many diseases.