Hydrozoning is the horticultural practice of selecting and placing plants with similar water requirements together so that they can be watered without under watering the thirsty plants or over watering the more water conservative plants. In this guide we will share with you the difference between One drop zones, Two drop Zones and Three drop Zones. We will also share with you the most popular and best performing One drop Zone plants available on the market today. Our suggestions cover shrubs, flowering plants and ground covers. Page 1
For example a rose needs regular watering whilst lavender needs infrequent watering and grows happily the natural rainfall. By planting these two plants together or adjacent to each other, you end up torn between giving the rose enough water to thrive and bloom but the same amount of water will be drowning the lavender. Alternatively giving the lavender infrequent water, will stress and eventually kill the rose. Hydrozoning can be applied to any size garden from a balcony garden to a vegetable garden, to a town house garden and to a large garden thereby conserving our most precious resource, water. Hydrozoning is not only done during the design of new gardens but can be applied to existing garden by transplanting plants to a more appropriate zone. Page 2
Let s look at the three hydrozones: One drop zone low water use: These plants are drought tolerant and thrive in hot, dry conditions with very little water. These plants therefore have low water requirements and need infrequent to almost no watering. These plants only have to be watered when they are first planted and while they are establishing themselves, after that, they can be left to survive on rainwater or the occasional watering. Plants that fall into this category are generally indigenous. These plants generally have grey and silver coloured leaves, plants that have a velvety covering on their leaves, plants with small foliage. Some plants that fall into this category include abelias, agapanthus, aloes, bougainvillea, cacti, succulents and strelitsias. Vegetables and herbs that fall into this category include artichokes, cabbage, cauliflower, radish and thyme, rosemary, sage cabbage, cauliflower, radishes and oregano. (For a fuller list of zone one plants, see appendix 1.) Ideally thirty to sixty percent of a garden should fall into this category. Page 3
Two drop zone medium water use: The majority of plants fall into this zone and are said to have medium water requirements which means they do not need to be watered every day but require water when the soil has been dry for over a week. Some plants that fall into this category include salvias, geraniums, pelargoniums, hibiscus, petunias, verbena and zinnias. Vegetables that fall into this category include parsley, broccoli, Brussel sprouts, potatoes, onions, beetroot, carrots, peas, peppers, beans, rhubarb, parsnips and mealies. Ideally twenty to forty percent of a garden should fall into this category. Page 4
Three drop zone high water use: This zone in the garden receives the most water - these plants are thirsty! Plants in this zone they love water and like to be kept moist. Some plants that fall into this category include lawns, roses, arum lilies, ferns, foxgloves, fuchsias and impatients. Vegetables that fall into this category include lettuce, celery, watercress, Swiss chard, rocket, spinach, asparagus, cucumber, tomatoes, brinjals, pumpkin and butternut. Ideally only ten to thirty sixty percent of a garden should fall into this category and this area should be a focal area within the garden, placed in areas that that require maximum effect, for example just off entertainment areas. Most plant sellers these days list the water requirements of the plants, dividing them into low-, medium, and high water requirements or one drop, two drop and three drop water requirements. Page 5
Appendix 1 One Drop Zone Unthirsty Plants Shrubs Coleonema, common name Confetti Bush This evergreen shrub has a fine, heather-like appearance and produces masses of small star shaped flowers in shades of pink or white which are sweetly scented. Frost tolerant and wind resistant. Duranta sapphire showers can be grown as a standard or shrub or small tree 3m high. This shrub is quick growing, evergreen and has dainty sprays of forget-me-not flowers in various shades of blue which are followed by long lasting dense drooping spikes or very showy orange berries Page 6
Freylinia tropica, Blue Honeybell Bush can be grown as hedges, balls or lollipops. This hardy, slender, evergreen shrub has fine leaves that are wind resistant. Bears small blue flowers. Nandina Domestica- (Sacred bamboo- heavenly bamboo) A dense shrub with fine delicate foliage which has white flowers in summer, followed by red berries in autumn. Leaves change colour in autumn providing red foliage throughout winter. Attracts birds to the garden. Grows in sun and semi-shade. Page 7
Plumbago a bushy compact shrub that produces masses of blue flowers, from late spring to autumn. Makes an excellent informal hedge plant, if clipped too severely flowering may be impaired. They will withstand drought and wind with some feeding and watering they will reward you with a long lasting brilliant display of flowers. Plant in a sunny to semi-shaded position. Will grow in poor soil. Frost tolerant. Salvia chamelaeagnea, commonly called Rough Blue Sage is an evergreen, dense shrub with bright green leaves that produces bright blue flowers with white and cream markings. Plant in full sun. Semi-frost tolerant. Page 8
Tecoma capensis, commonly called Cape honeysuckle is a fastgrowing shrub which produces flowers which vary from red, deep orange, yellow to salmon throughout most of the year. Flowers are tubular in shape and attract nectarfeeding birds. Commonly used for informal screening but can be trimmed to form a hedge. Plant in full sun or semishade. Page 9
Flowering indigenous plants Agapanthus wide variety medium sized plants with blue or white flowers and strappy leaves. Plant in sunny position. Aloearborescens and Aloe ferox have bluey-green large sculptural leaves and intense red, organe and yellow flowers that attract birds. Page 10
Dietes Grandiflor, commonly called Wild Iris thrive in semi-shade and full sun and are frost tolerant. Iris-like plants with evergreen sword-like foliage forming clumps Blooms last for a day with new flowers opening every day Kniphofia, commonly called Red Hot Pokers have sword like leaves and produce spikes of upright, brightly coloured flowers in shades of red, orange and yellow, that attract bees, butterflies and birds. Cold and frost tolerant. Page 11
Osteopermum, commonly called Cape Daisies are an easy growing plant which produces masses of daisy like flowers from spring through to autumn. Plant in sunny position. Page 12
Strelitzia has strappy leaves, flowering throughout the year with flowers that are a combination of orange, white and blue. Tulbaghia violacea commonly called Wild Garlic has long narrow grey-green leaves and purple coloured flowers. Page 13
Other flowering plants Dianthus commonly called Dwarf Carnation is a busy compact plant that flowers throughout the year. Plant in sunny position. Cold and frost tolerant. Dusty Miller or more correctly Senecio cineraria has unusual silvery grey foliage and small yellow flowers. Plant in full sun or semi-shade. Tolerates light frost. Page 14
Gladiolus is a perennial favoured for its beautiful showy flowers which come in a variety of colours. Plant in sunny position. Gaura has butterfly like flowers of pink or white which grow on long stalks. Flowering profusely for most of the year from spring to autumn. Plant in sun or semi-shade. Frost and Cold Tolerant. Page 15
Lavandula come in a wide variety and all members of this family will thrive in Zone 1 areas. Lavender Blue Canaries is the most aromatic of all the Lavender plants and has feathery bright green foliage and small dark blue flowers, which flower throughout the year. Excellent when planted on mass. Easy to grow and will even grow in semi shade. Lavandula stoechas (Lavender stoechas) is a compact plant with fragrant grey-green foliage which has unusual flowers with pale purple petals. Evergreen. Plants can tolerate semi-cold and frost. Page 16
Marigolds have dense feathery foliage and yellow or orange carnation like flowers that bloom prolifically from summer through to autumn. Plant in sunny position. Verbena grow happily in virtually any type of soil and flower profusely throughout the year, in shades of white, red, pink and purple. Page 17
Ground covers Erigeron this dainty plant has fine light airy textured leaves and stems and produces small white daisy-like flowers tinged with pink. Flowers throughout the year. Plant in sunny position. Cold and frost tolerant. Delosperma also known as vygies is a succulent ground cover that produces daisy-like flowers in a wide variety of colours from late winter through to spring. Will grow in sandy soil. Plant in sunny position. Cold and frost tolerant. Page 18
Hardy Gazanias will thrive in most soils, no matter how poor the quality and still produce bold-coloured, daisy like flowers throughout the year. Cold and frost tolerant. Portulacas are low growing ground cover commonly called the moss rose. They flower in a variety of colours pink, red, yellow, orange, deep lavender, cream and white. Page 19