Diosma hirsuta ' Blue Downs' as well as most of the species found in the Rutaceae family are best grown in your garden in full sun, in soil that is alkaline to acid, well-drained and composted. Prepare the bed by digging over the soil, adding compost and a slow-release fertilizer. Water the area before planting. Plant out in-groups of 3 to 5, 20 to 30 cm apart. They are slow- growing plants and should not be planted too close to fast-growing plants. A layer of mulch is added after planting and annually to keep soil and roots cool in summer, retain soil moisture and reduce weeds. Buchus are best planted out during autumn, winter and spring. Plants require good watering in winter and moderate watering in summer. Do not allow plants to dry out and avoid cultivating the soil around the roots of these fynbos plants. They are water-wise plants and once established in your garden they will survive long periods of drought and will withstand a fair amount of frost.

Buchus are used as accent plants or in a mixed fynbos bed with companion plants such as Erica, Restio, Phylica species, Pelargonium betulinum, herbaceous perennials such as Lobelia valida, Geranium incanum, as well as other buchu species such as Agathosma lanceolata (honey buchu), Adenandra uniflora (china flower) and Coleonema album (white confetti bush).

Buchus can be successfully grown from seed or cuttings. Viable seeds develop after flowering when the seed capsule darkens and should be harvested before the seeds are dispersed. Seed collected from fully ripe capsules has a higher germination percentage. If seed is picked too early, the embryo will not ripen and the seed will not be viable. Fresh buchu seed is sown in autumn (March to April). The seed are sown into a tray containing a well-drained medium of equal portions of sand, loam and compost. Use some of the medium to cover the seed and water. Place in a covered area with good light and air circulation. Keep medium damp. Germination occurs in one to two months.

Young seedlings are pricked out into 0.5 litre bags when four true leaves have developed, using a fynbos medium. Feed plants regularly but sparingly with a well-balanced ferilizer. Pinch out the growing tips of the seedlings to encourage bushy growth. Flowers are produced after two years.

After flowering, plants develop new shoots or branches, which are ideal for tip, stem or heel cuttings. Collect plant material early in the morning to reduce stress. Cuttings have the advantage of producing a larger flowering plant quicker than seedlings. Tip cuttings, 50-70 mm, are taken from the current year's growth. Prepare cuttings by making a clean cut below the node and remove a third of the foliage. Dip the base of the cutting in a rooting hormone. Firmly place the cuttings in a medium of 50% bark and 50% polystyrene and water cuttings with a fungicide. Ideally these cuttings should now be placed in a well-aerated propagation unit with a bottom heat of 24ºC. Rooting occurs in 9 to 11 weeks. Carefully pot the rooted cuttings using a well-drained, humus-rich, fynbos potting medium (2 parts leaf mould, 1 part coarse sand). Plants will be ready for planting in 7 to 8 months, ideally during autumn to spring. Feed regularly with a well-balanced nutrient. Yellow leaves can be treated with an application of iron chelate.