There is a record in the Guinness Book of World Records that confirms:
"The oldest tree known to have been planted by a human rather than by natural seeding is a 2,300-year-old sacred fig or bo-tree (Ficus religiosa) that has been named Sri Maha Bodhiya, and stands in Anuradhapura, Sri Lanka. It was planted there in 288 BC. The mother tree from which this specimen was propagated was none other than the famous Bodhi tree under which Siddhartha Gautama the Lord Buddha was sitting when he gained enlightenment"
Interestingly, there are many different dates quoted for the official planting of this sacred tree ranging from 288BC, 249BC, 244BC and 236BC.
Sri Maha Bodhi is known as one of the Atamasthana or the 8 places of veneration in the ancient sacred city of Anuradhapura (which is a UNESCO Wold Heritage site).
The ancient kings over time have built a variety of structures, including fences, water canal, walls and railings around the sacred fig tree for its sanctity, preservation and protection. As to be expected, there is security in the form of the Sri Lankan army protecting the sacred site. And, there is signage as you enter the Sri Maha Bodhi compound kindly requesting that pilgrims and visitors refrain from smoking, wearing head covering (i.e. caps, hats, helmets), footwear (note - there is a small hut with an attendant where you can securely store your footwear near the main entrance), and wearing black or dark clothing (i.e. white clothing is usually worn as a sign of respect).
It's quite a large rectangular compound once you pass the Maha Viharaya and the security checkpoint, though most pilgrims and visitors head straight for the sacred tree, and fail to take in the rest until later. If you have visited for one of the poya or full moon day, then you quickly realize it makes sense to have this large space to fill to capacity.
Usually pilgrims bring flowers to offer at the Buddha shrines scattered around the compound. Or some make special prayer flags or wishes and place them on the bo-trees located around the wider compound area.
Pilgrims also make other offerings to the sacred tree of atapirikara (this comprises eight items usually offered to monastic Sangha that includes an alms-bowl, three robes, belt, razor, water-strainer, and sewing needle), bodhi puja, medicines, milk-rice, robes and more. It's also possible to offer water to the sacred tree to ensure its health and longevity.
Usually, there are male attendants clothed in white who have access to those shrines who will take the offerings up to the sacred tree to offer on your behalf.
Offerings are considered meritorious in the Buddhist tradition. There are three bases of merits in Buddhism - they are giving (dāna), virtue (sīla) and the development of meditation (bhāvanā). There are also other ways of making merit that associated with listening to Dhamma, dedicating merits, rejoicing another's merit, teaching Dhamma and more. In the Buddhist practice, the accumulation of merits directly contributes to a person's spiritual development and liberation. Some say, without merits, the spiritual path can be more challenging, arduous and lengthy.
If you're non-Buddhist and visiting Sri Maha Bodhi my suggestion would be to offer some flowers near the sacred tree with an intention for wellbeing (and to overcome any challenges you may be facing). When I visited with my mother last month, she had brought some swiss chocolates with her and wanted to offer them to some monks and nuns. So while we were observing the pujas and the generous activities of pilgrims around the sacred tree, we wandered around the compound and every time we came across a monk or nun (usually meditating or chanting), we offered chocolates to them. I could see locals and pilgrims looking on with interest.
There are many historical and significant carvings and motifs to be seen around the sacred site. You have to take the time to slowly wander around
Many pilgrims will sit and chant or meditate near the tree. Sometimes you can see monastics quietly meditating within the compound.
I took this video at Jaya Sri Maha Bodhi...
According to the Mahavamsa (the Great Chronicle of Sri Lanka), branches from the sacred fig trees of all the Buddhas born during this kalpa (aeon) have been planted in the same place as where Jaya Sri Maha Bodhi stands today in Anuradhapura. It goes on to state that the branch of Buddha Kakusandha's tree was brought by a nun called Rucananda; Buddha Konagamana's by Kantakananda; Buddha Kassapa's by Sudhamma and, as we know, Buddha Gautama by Sanghamitta.
For more information on this sacred place, take a look at the official website of Anuradhapura Maha Viharaya.