There are many Dorset gardens you can visit and I will gighlight some of the main ones below but this is not an exhastive list by any means. Abbotsbury subtropical gardens can be found on the Abbbotsbury page.
Kingston Maurward Gardens is just outside of Dorchester and is set in gently undulating countryside. The gardens surrond Kingston Maurward House and is a very peaceful and tranquil setting, with its large lake and the walks around it a real pleasure. The garden is laid out in the Jardin Anglais style made popular by Capability Brown and there are several smaller parts of the garden each having their own theme including a delightful walled garden.
Set in 8 acres just outside of Weymouth, bennetts Water Gardens hold National and International collections of water lillies. These flower from spring through autumn in the best display of water lillies in the UK. There is a Monet inspired Japanese Bridge as the centrepiece with careful thought gone into seating areas so you can sit and take in the views in this most tranquil and beautiful setting.
Athelhampton Gardens is situated just outside of Dorchester. These formal gardens, designed in 1891, is a series of spaces including the great court with its famous giant pyramids. Water features heavily with fountains, pools and a formal canal. Planting is simple but effective, with roses, clematis and tulips.
Situated near Beaminster, Mapperton's terraced valley gardens surround the Manor House. Mapperton Gardens was recently the setting for Jane Ausitin's Emma and it is not hard to see why it was chosen. With its walled croquet lawn, an orangery, an ornate pavillion, the Italiente formal garden with its fountains, ponds and herbacious borders, a 17th century summer house, hedged fishponds, rare tress, woodland, spring gardens and autumn colour. Worth a visit, or maybe even two.