Visual Arts: Landscapes 06 marshals three complementary approaches to landscape with works by Malachy Costello, Helena Gorey and Stephen Rennicks, writes Aidan Dunne.

Of the three, Costello takes the most orthodox approach. He makes paintings based on the rural landscape in winter. From Croghan, Co Roscommon, he is based not far away, in Drumlion, and his favoured terrain is around his home, where north Roscommon, Leitrim and Sligo meet and interweave.

He likes expanses of fields dusted with snow or frost, and his more representational accounts of them, on both small and large scales, are bold, convincing paintings. But he also takes the patterns produced by light falling across the grain of the frozen ground as sources for virtually abstract, all-over paintings. He sees no marked division between the two kinds of work and he's surely right about that. The more abstract paintings have a level of vivacity and immediacy easily on a par with the representational works, and are clearly derived from the same source.

Costello relishes the feeling of potential energy contained in the empty expanse of a winter field. This real space becomes, for us, a charged, imaginative space. It's worth noting that he is altogether comfortable painting on a really large scale. The only weak note is struck by a series of charcoal drawings: to be sure, they are very competent, but seem curiously underpowered by comparison with the paintings.

In her work, Gorey, who is based in rural Co Kilkenny, also explores her local surroundings. Two Trees, an installation, includes a series of photographic prints and a video charting daily and seasonal changes by focusing on a stand of trees on the horizon line. There is a calm, meditative quality to the video. Ambient noises add to the sense of space. There are some beautiful images among the photographs. Yet overall it comes across as unresolved, as a work in progress. Merely displaying a video together with a succession of prints does not an installation make. Perhaps slide-projected images together with a soundtrack would have been more effective. Who knows? Somewhere in the material Gorey has amassed, there is a viable piece, but probably not in its present form.

Rennicks is an intriguing conceptual artist who has proved himself willing to invest time and energy in lengthy projects that are hardly likely to attain any public profile at all, but do have the potential to connect with an audience on a one-to-one basis, in an almost clandestine, underground way. His Junk out of Context featured his own interventions in commercial audio and video items from charity shops in Dublin. The amended items were surreptitiously reintroduced into the shops.

Rennicks has lived in Leitrim for more than a year now, and Imagine Black Lough stems from Black Lough, a work made earlier this year. For the earlier piece, he posted information on his website about marking a trail to the eponymous lake, a remote, neglected body of water near Oakport Woods in Co Roscommon. He invited people to imagine the lake, but also opened up the possibility of them setting out to try to follow the trail and find Black Lough themselves.

So far, so good. Revisiting the lake in the gallery context obviously posed different problems. He could just have documented the original project and, in the event, that is partly what he does. He notes that he was initially interested in the idea of inviting people to test their imagined view of something with the reality, or have them decide not to check out the reality for themselves.

This opens up a number of interesting ideas: the postmodern retreat from notions of the "real", the denial of nature that accompanies suburbanisation and, in quite a different vein, the romantic idea of a lost or hidden destination, like a pirate's treasure map in popular fiction. He even provided several tangible "treasures", or in Hitchcock's famous coinage, McGuffins, in the form of CDs, for those who made it to the lake.

Imagine Black Lough lets us off lightly compared to the original piece. We can, in the comfort of the gallery, experience varieties of documentation, including projected imagery, recorded sounds and glass jars recovered from woodland adjacent to the lake and now filled with lake water. Perhaps there's a bit too much in all of this, but it does work. It engages with the audience on a number of levels and invites us to think for ourselves.

It's particularly interesting that Landscapes 06, although awkwardly titled, is a thoroughly contemporary, professionally presented show that draws profitably on the Dock's context. It features two locally based artists who are concerned with their immediate environment and wider issues. All in all, a good example of what regional arts centres can do.

At the Douglas Hyde Gallery, carvings and watercolours by German artist Paloma Varga Weisz feature in what has become a series of laid-back, quirky shows. Weisz's work has a curious intensity, marrying an anachronistic Gothic sensibility to jokey surrealism. Yet maybe there is no such distinction to be made. Her human-animal hybrids and anthropomorphic animals are in a sense surreal, but also recall a closed-in world of medieval superstitions and folk myths.

The sculptures are particularly compelling. Her Hairy Woman and Fighting Dog are extraordinary creations. The watercolours are more hit and miss but at their best, creepily fascinating.

Alice Roden's six intricately woven cushion covers in Gallery 2 comprise an appropriate partner for Weisz's carvings. They take a traditional craft form and, without eschewing any of its values and skills, employ it in an unselfconsciously contemporary way. Roden engineers overall evenness and serenity from layers of dense, complex patterning.

There is a patient, contemplative quality to her accumulation of ingeniously plotted details. But she also maintains a consistent tension between the part and the whole, never settling for a coherence that might  seem too easy or pat - in one case dramatically so.

• Reviewed - Landscapes 06, The Dock, Carrick-on-Shannon until Sept 3 (071-9650828) Paloma Varga Weisz, sculpture and watercolours; Alice Roden, Douglas Hyde Galleries 1 and 2 until Sept 16 (01-6081116)