Glossary of Gardening Terms

 
Acidic soil Substances which have a pH value between 0 and 7 are acidic; 0 being the most acidic, 7 = neutral. In practice, the most acidic soil which plants will grow in is 5.5. Few plants tolerate this & most acid-loving plants will grow in soils with a pH of 6 – 7. Simple soil test kits are widely available – this will give you an indication of your soil acidity/alkalinity.
Alkaline soil Substances with a pH value between 7 and 14, 14 being the most alkaline. Lime-loving plants grow in soils with a pH value of 7 – 8.
Boggy soil In simple terms if you can make mud pies from it, then its boggy. If you dig a hole and it fills with water, you have boggy soil. You can make an artificial bog garden by digging out an area of soil, lining it with plastic and replacing the soil on top. It is important to puncture the plastic in a few places because, although water retention is required, it will become stagnant if not allowed to drain away and be renewed by fresh rainwater.
Cactus compost Used for growing succulents and Cactus, this can usually be brought ready mixed from garden centres. It is essentially 3 parts John Innes No.2 to 1 part grit so you could mix your own. See Loam based compost.
Corm An organ which works in much the same way as a bulb does, situated underground, it stores all the plant needs to grow. They are usually flatter than a bulb in appearance.
Cultivar see plant names.
Dappled shade An area which is shaded by trees with open canopies, allowing small amounts of sunlight to filter through.
Drought tolerant The emphasis here is on tolerant. Plants may be able to tolerate drought but sometimes there can be a reduction in flower size, colour and the over all size of the plant. Also, plants can take longer to establish and begin flowering in very dry conditions.
Family see plant names.
Form see plant names.
Frost hardy Plants which will tolerate temperatures down to -5°C (23°F)
Full or Deep shade An area which receives no direct sunlight at all. Bear in mind the soil beneath large trees will be very dry and low in nutrients.
Genus see plant names.
Half hardy Plants which will tolerate temperatures down to 0°C (32°F)
Hardy Plants which will tolerate temperatures down to -15°C (5°F)
Hard pruning This refers to plants which either need or can tolerate drastic pruning. Always leave the lowest set of healthy shoots on a plant and never cut back into non shooting wood or prune when a plant is dormant unless instructed otherwise.
Humus-rich soil In simple terms this means leafy soil. This type of soil naturally occurs beneath deciduous trees, where the leaf litter rots down and is incorporated into the soil resulting in a lovely, light and nutritious growing medium for plants. Any soil can be improved with humus by either digging in organic matter such as compost or really well rotted manure. Another method is to dig in leaf mould (See LEAF MOULD).
John Innes No.1, 2 or 3 See LOAM BASED COMPOST
Leaf mould A fantastic and free material which can be used as a mulch or dug into the soil to improve the level of Humus (see Humus-rich soil.) You do not need a large garden or even a compost heap to make leaf mould. Simply collect fallen leaves in autumn and pack them tightly into black dustbin bags, make some holes in the bottom to allow the material to breath and drain as it rots down. Spray some water into the bags to wet the leaves if they are dry. The bags can be stored out of the way in a corner and after a year you will have a semi-rotted material which can be used as a mulch or can be dug into problem soils such as clay, sand or chalk, to improve the structure. After two years you will have well-rotted material which will be almost weed free and can be used as a substitute for peat-based compost. Bear in mind that a full bag of leaves will rot down to about a quarter of a bag so collect as many as you can and maybe offer to collect your neighbours' leaves. If you have a large amount of leaves you could make a large, open-top pen with chicken wire sides and deposit them into this and simply leave them to get on with it. You can also add fresh grass cuttings to the leaf mould but try not to incorporate any soil or other garden waste.
Loam based/ John Innes compost This is a soil based compost rather then peat based and is best used for long-term container-grown plants. It has much better moisture and nutrient retentive properties than multi-purpose compost which is only suitable for growing annuals, seedlings and cuttings. John Innes No.1 is the lowest in nutrients and is suitable for some Cactus and Succulents. John Innes No.2 is slightly higher in nutrients and is used for the majority of Cactus and Succulents see Cactus compost. John Innes No.3 is the highest in nutrients and is recommended for most container grown plants. Always add some grit to the compost to ensure good drainage and remember to feed plants regularly. See Top dressing.
Manure Manure can provide large amounts of the three basic Chemicals needed for plants to grow- nitrogen, phosphorus and potassium There are many different types of manure, too numerous to mention them all here. The most important thing is to ensure that any manure has been rotted down for at least 6 months. Fresh manure is very high in nitrogen which can burn the roots of plants if dug into the soil or burn any top growth if applied on top of the soil. Chicken manure is very potent and needs to be rotted down for at least a year. There is not much to choose between Horse and Cow manure except that Cow's stomachs are much better at digesting seeds than Horses'. Therefore Cow manure is usually freer of weeds.
Marginal plants Plants which can be grown in shallow water no deeper than 30cm (1ft) Any deeper than this and you will need proper pond plants.
Moist, well drained soil This may sound like a contradiction in terms but it simply means soil which remains damp beneath the surface during dry weather but does not become waterlogged in winter.
Neutral soil Soil with a pH level of 7. See ACIDIC & ALKALINE SOILS.
Part shade An area which is shaded by trees or buildings for most of the day but receives some direct sunlight at some point in the day.
Reliably moist to Boggy soil This soil is required for moisture loving plants such as Caltha (Marsh Marigold) Commonly grown in a bog garden, these plants can also be grown in normal soil as long as it is always moist, even in dry weather.
Rhizome A fleshy stem which spreads underground, sometimes breaking the surface of the soil, which acts as a storage organ.
Species see plant names.
Subspecies see plant names.
Tender plants Plants which may not survive temperatures below 5°C (41°F)
Top dressing This is recommended for plants grown in containers for and extended period. It is a suitable method of feeding for the majority of container grown plants with the exception of very vigorous plants such as Bougainvillea or fruiting plants which need feeding frequently with a liquid fertiliser. In the spring, when plants are in active growth, scrape away the top layer of compost (1/2 an inch or so) and apply a small amount of slow / control release fertiliser, following the manufactures instructions. Apply a fresh layer of compost on top. Make sure you obtain this in loose form, not the tablet-like products designed for use in hanging baskets. Most composts only have enough fertiliser in them to feed plants for a few weeks or at most, a few months. It is important therefore to renew these nutrients regularly. This can be done by using this method or by feeding with a liquid feed on a regular basis.
Trim lightly This refers to plants which require only a light pruning either after flowering or in the spring. This is aimed at tidying the plant up or preventing it from putting too much energy into producing seed, concentrating instead on putting on healthy growth for the following season.
Tuber A fleshy root found on plants like Dahlias which works as a storage organ to provide the plant with all its needs.
Variety see plant names.
Well drained to dry soil Soil which is always free draining and is prone to becoming dry in summer.
Well rotted manure see MANURE.