Companion Planting is the placement of various crops in close physical proximity to one another so as to symbiotically compliment each others health, vigor, growth and the flavor of their produce. It also naturally involves separating plants whose development is antagonistic to each other.
Best Companions for Gooseberries are Beans & Legumes, Tomato, Chives, Tansy
Gooseberry doesn't have very many known friends in the plant realm , nor does it have very many enemies either.
Back in the 1930s Gooseberries made some enemies amongst the human realm when they were banned in Boston, as well as the rest of the USA because it was believed they carriers of white pine blister rust. White pine blister rust was decimating the logging industry. They should be kept away from susceptible trees which in addition to white pine also includes Black locust and sugar maple.
Alleopathic trees such as walnut, which emit a phytotoxin known as juglone via their roots which destroys most other plants within its reach are not a problem to the gooseberry as gooseberries are juglone resistant.
Beans, in particular broad beans make good companions. Beans fix nitrogen in the soil as is well documented, nitrogen enriches/fertilizes the soil for surrounding plants. Gooseberry is not a heavy nitrogen feeder, they use more potassium, beans use potassium also but not a tremendous amount.When planting beans and gooseberry together, a light amendment of potash would be helpful. Broad beans, beans which grow in pods, repel the dreaded gooseberry sawfly, an added perk.
Tomatoes are also good companions for gooseberry. The tomato is believed to repel some insects that feed on gooseberry. The scent of gooseberry is believed to repel some pests of tomato plants - [unproven].
Tansy Planted under fruit trees acts as a pest repellent it deters flying insects, - Japanese beetles, striped cucumber beetles, squash bugs, ants and so forth and is a good companion plant for gooseberry. Tansy Stems and Leaves are TOXIC to People, Pets and Livestock.
It is also important to point out that gooseberry bushes are also toxic as they contain hydrogen cyanide. Birds, livestock , pets, wild life or people that eat the green leaves are susceptible to possible fatal consequences.
Chives are another plant believed to enhance and protect gooseberry. Chives actually help to prevent some pathogenic issues that afflict gooseberries and other similar fruits and berries.
It has been demonstrated that chives When planted with apple trees will help to prevent apple scab. Gooseberry mildew is a related plant malady that chives can also help defend against. A tea made from chives can be used against mildews on gooseberry plants, such as downy and powdery mildew.
Periodic spraying of baking soda helps control many forms of mildew. I've had success using a mix of Neem Oil which is water soluble, and baking soda, a tablespoon of each to a quart of water. The Neem oil serves multiple purposes, primarily insect control and the baking soda helps fight mildew.
Wormwood, a very modest amount, mixed in with gooseberry will help suppress plant rusts. As a border, wormwood keeps animals away from the garden, also known as absinthium and artemisius, it grows to 5 feet tall and is very aromatic. It contains a chemical called absinthin which is toxic to many other plants . It is best kept in Planters or a safe distance from other plants. Tarragon, a close relative of wormwood will also work but not nearly as effectively. Wormwood emits a chemical that is toxic to many other plants , tarragon does not - Tarragon has many more uses in the herbal realm - wormwood doesn't.
Other fruits and berries such as currants, elderberry and strawberry can be grown well with gooseberry. There are no documented symbiotic relationships relative to flavor enhancement, pest suppression and so forth, but they do share many of the same requirements. So long as the care -taker [you] is vigilante competition for resources should not be a major issue.