May is one month of the year devoted to the Blessed Virgin Mary, the Mother of God. The origins of the May devotions are vague, but devotion to the Blessed Virgin goes back to the early years of Christianity. Marian devotions are usually extra-liturgical but songs to or about Mary can be found occasionally during Mass, or in the Divine Office.
It may be the connection, in the Northern Hemisphere, with Spring and new life that brings about the association of this season with Mary. Mother's Day falls in May. The Easter season, the ultimate celebration of new life, falls partly in May.
One way of observing May as a month dedicated to Mary is to create a "Mary Garden". Mary Gardens have existed since the medieval period. If you like to garden, or are interested in learning, this could be an interesting way to exercise your faith. It is also something that a family could research and work on together.
Many plants have historical associations with Mary. These links are often very fanciful, but that is really not an issue. If a plant in some way causes us to recollect on Jesus' mother, you can be sure we are doing something that Jesus himself did!
Once you have decided where to place your garden, and have prepared the soil, find a statue to place in the garden. It does not have to be very big, but ensure that it is weatherproof. If you are energetic, you may wish to create an elongated garden to emulate a rosary, or the Stations of the Cross.
Choose flowers that will do well in your climate and soil conditions. Also be aware that some flowers, such as Foxglove, are poisonous. Some plants, such as mullein (Our Lady's Candle) are weed-like. If you speak to a local gardening specialist, they can advise you in your choices. Planting perennials may make gardening easier and can give children something to follow and remember year after year.