Much has been said, pro and con, about Hardy's style in his fiction. It is easy to say he has a clumsy style or an adequate style or an intermittently effective style. A demonstration of some particular aspect of his style is perhaps more useful.
Hardy's narrative style makes use of several kinds of imagery, including a number of figures of speech using analogies drawn from the setting of his story. Consider such a sampling as the following: "Eustacia's journey was at first as vague in direction as that of thistledown in the wind"; "the party had marched in trail, like a traveling flock of sheep; that is to say, the strongest first, the weak and young behind"; "[Grandfer Cantle] also began to sing, in the voice of a bee up a flue"; "Grandfer Cantle meanwhile staring at [Christian] as a hen stares at the duck she has hatched"; "in her winter dress, as now, [Eustacia] was like the tiger-beetle, which, when observed in dull situations, seems to be of the quietest neutral color, but under a full illumination blazes with dazzling splendor"; "[the settle] is, to the hearths of old-fashioned cavernous fireplaces, what the last belt of trees is to the exposed country estate, or the north wall to the garden"; "[Clym] longed for death, as a field laborer longs for the shade"; "Fairway gave a circular motion to the rope, as if he were stirring a batter"; "[Eustacia] had entered the dance from the troubled hours of her late life as one might enter a brilliant chamber after a night walk in a wood"; "the leaves of the hollyhocks hung like half-closed umbrellas." In the first of these, the term carrying the analogy comes from nature; in the second, from the characters' daily activities on the heath.
In short, Hardy's imagery is appropriate to the world of his story and effective in conveying what, at a given moment, he wishes to show, not merely say.