Category Archives: Outdoor classroom

Outdoor Classroom: twin scaling

photo 1 - Copy1) Twin scaling is a way of increasing the number of bulbs more quickly than by other usual methods. A single bulb can yield up to 30 or more baby bulbs (bulblets) over a period of a season. It only works with proper bulbs – not corms, tubers and rhizomes. Bulbs need a base plate and a layered construction to be twin scaled – eerily similar in form to the common onion shown here.
photo 2 - Copy2) Twin scaling works well for bulbs such as narcissi (daffodils), crinums, galanthus (snowdrops), nerines, amaryllis, hippeastrums, lachenalias and some lilies. Wash the bulb and remove any outside coating and old roots. Make up a weak solution of household bleach – about 1:10 bleach to water – and dip the sharp knife and bulbs. Clean working conditions and hygiene are important to prevent disease and the transfer of any viruses.
???????????????????????????????3) Remove any offsets already formed, making sure you keep some of the base plate with them. The base plate is where the roots grow from. Cut the top third off the bulb (both offset and top are visible to the left in the photo). Cut the main bulb into quarters or eighths, depending on the size of the bulb. Each piece must have some of the base plate remaining attached. The larger the bulb, the more sections you will get.
???????????????????????????????4) Peel off two scales together, attached to some of the base plate. Keep your knife clean and sharp so you can cut through the base of each section more easily. It does not matter if you have three or more scales but if you do not have part of the base plate, the process will not work. A bulblet will form between the two scales on this base plate.
photo 5 - Copy5) Plant the scales in a pot or tray filled with seed raising mix. Press them down deeper than in the photograph until just the tip is visible. Water them in and keep the tray in a warm, reasonably dark position. The bulblets will form through the autumn and grow away in spring so it is best to twin scale when the bulb is freshly dormant. It is too late to twin scale autumn flowering bulbs because they are already starting to grow but you can do the spring flowering ones which includes narcissi such as this bulb.
???????????????????????????????6) If you lack the confidence to take each section down to two scales, you can stop at step 3 where you have cut the bulb into quarters or eighths. As long as you look after them, most sections will grow away into healthy, independent bulbs. It is probably easiest to start with a large bulb while you gain confidence. Most bulbs propagated by twin scaling will take at least two years to reach flowering size, sometimes longer.

Established espalier

Most of the drawings and photographs I have seen of espaliered fruit trees are at the initial stage, showing how to start. So when I saw established examples of espalier in England, I photographed them.
freestanding horizontal espalier1. The freestanding horizontal espalier. You can see clearly the advantages of a two dimensional plant. Good air movement will reduce disease. It is easy to tend the plant and the fruit all receives equal sunlight. You can also see that the supports are heavy duty. This is not an exercise to be done with a few bamboo stakes and stockinette ties.
The cube2. The cube requires some heavy duty framing but is quite stylish, even if I was worried by the top branch that was trained back on itself. Using a frame which gently rusts as it ages will make it less visually intrusive than the tanalised pine we often favour in this country. It is the plant shape you want to emphasise, not the support structure. This design allows good air movement through the centre of the tree.
??????????????????????????????????????????????????????????????3.The diamond row was visually the strongest in terms of pattern. I raised my eyebrows at the potential rubbing of bark where branches cross. Stem damage can let disease into the plant and a rule of thumb in all gardening is to avoid crossed branches. Presumably in an intensively maintained espalier, you are replacing the branches regularly with fresh growth so there is a bit of leeway if this is the look you want.
???????????????????????????????4. There is little doubt that your fan-shaped espalier will look better if you clad the fibrolite garage in old brick veneer and casually pose a stylish, vintage, terracotta forcing pot in front. The advantage of espaliering against a wall is the increase in heat for marginal crops. We don’t need to do it for apples and pears in this climate but I can see that it could work well for figs and some of the stone fruit.
???????????????????????????????5. I have mentioned trendy stepovers before – the training of an espaliered fruit at knee level. This is a dry climate technique and where rains are light and misty. Our torrential downpours will cause rain splash and spread disease faster than you can blink. We need maximum air movement and to be above the splash line in our humid climate. That said, you can see disease in this example. I have yet to see one which remains at step-over height all growing season.
???????????????????????????????6. These table and chairs are obviously not yet established. I offer them as an idea without comment, secure in the knowledge that regular readers will know exactly what my personal opinion is likely to be. However, for those who like a little novelty in their garden, here be they. I even recorded some instructions for you.
First published in the Waikato Times and reprinted here with their permission.

Digging and dividing clivias

???????????????????????????????1) Clivias are wonderfully adaptable plants for mild climates. Their ability to thrive in hard conditions, even in relatively deep shade and with a regime of near total neglect makes them an obliging garden plant, once they are established. They don’t like frost but woodland conditions will protect them. The reason they are seen as expensive and choice is because they take years to reach a saleable grade, not that they are difficult. However, given time, clumps can get very large and yield many divisions for replanting.

???????????????????????????????2) It doesn’t seem to matter when you divide them, though it would probably pay to avoid dry mid-summer. Like most perennials, they respond well to lifting, dividing and being replanted in ground which has been freshly dug over. The clumps can be large and heavy but this one was small enough to get out as one. Get as much of the root system with it as you can.

???????????????????????????????3) I hosed the clump so it was easier to see and to show what the base looks like, but this is not necessary. The fleshy base is easily cut with a garden knife or a spade. It is easier to control what you are doing with a knife and to make sure that each division has roots attached. If you try and pull them apart by hand, you are more likely to end up with a tuft of leaves and no base.

???????????????????????????????4) It pays to reduce the volume of foliage – this reduces stress on the plant which has undergone considerable disturbance and root damage. I took off about half the leaves where the root systems looked small.

???????????????????????????????5) I dug over the area where the clump had been growing before replanting, incorporating the leaf litter that was lying around. Fertilise lightly if you wish and spread compost to enrich the soil and act as mulch.

???????????????????????????????6) In digging over, I found the missing rake head from many years ago when the area was first planted. It is a bit like trowels and secateurs in the compost heap but they usually reappear within the year (albeit in just as poor condition).

Published in the Waikato Times and reprinted here with their permission.

Outdoor Classroom: multiplying succulents

Photo 1If everybody realised just how easy it is to strike succulents from cutting, nobody would buy these plants unless they were new or exciting. This Crassula ovata (Jade Plant or money plant – very good for feng shui, apparently) could easily generate 30 good sized plants or many more smaller ones.
Photo 2The ground-hugging types which form rosettes are easy to lift and divide. As long as they are replanted in full sun with excellent drainage and light soils, each little rosette will form new roots when nestled into the soil. Tidy up the rosette first by removing dead leaves to avoid them holding moisture in the rotting foliage.
Photo 3Even succulents with well defined branches will grow. This is Aloe plicatilis or the fan aloe. Unlike usual leafy cuttings, succulents can be struck from very large pieces and you can expect close to 100% success rate. Cut to a balanced shape. Place the cutting in an airy spot and leave it for a few days to dry out. This reduces the chance of rotting before it creates roots.
Photo 4Stick the cutting into a pot filled with a free draining potting mix (we use granulated bark) It is better to use a mix which does not have much fertiliser in it but this is not critical. You can equally put them straight into the garden in a free draining, dry position. It may be necessary to stake the top if you have a heavy cutting so that it remains standing. Do not try and keep it firm by compacting the soil or potting mix because you want maximum drainage.
Photo 5Make sure that the cutting does not get waterlogged while you wait for it to form roots, but it will need an occasional wetting. In a few months, most plants will have started producing roots but it will take time for a large or heavy cutting to develop enough of a root ball to keep it standing upright.
Photo 6Most succulents, including the popular burgundy black aeonium whose name few can remember and even fewer can spell (Aeonium arboreum ‘Zwartkop’ or ‘Schwartzkopf’), sempervivens, aloes and many cacti can be increased this way. It is a good activity to share with children.

Outdoor Classroom: Sowing seed in trays

Photo 11) Sowing seed should save you money, especially with vegetables and annuals and it is also the way of getting plants which may not be available otherwise – such as dwarf daffodils, English snowdrops or rhododendron species. We use polystyrene mushroom trays which we have been continuing to use for up to 20 years. Wooden or plastic trays can also be used but you need around 10cm in depth and plenty of drainage holes. Egg cartons can be used for quick turn around crops such as lettuce or peas. You can also reuse the punnets that come from garden centres. Mark likes small individual pots for vegetables.
Photo 22) It is preferable to use proper seed raising mix which has less fertiliser in it than potting mix because fertiliser can burn young plants. These mixes are sterile, so you know when you see shoots that it is your seeds germinating. You can use garden soil if you want to but coarsely sieve it first to get rid of larger lumps and you need some fine sand or similar to sprinkle over the seeds on top. A home made sieve is fine. You can’t use unwashed beach sand because plants don’t like salt. A bag of seed raising mix is easier and goes a long way so is not expensive.
Photo 33) When filling with mix, tamp it down to get rid of air bubbles by pressing on top of the tray. If you are using egg cartons or individual cells, sharply rap the container on a hard surface to get the mix settling further. However, if you are using garden soil, don’t compact it.
Photo 44) Large seed can be hand placed but fine seed is traditionally tapped out of the hand as shown in the photograph or dispersed in small quantities from a piece of folded paper. It can also be dispersed by pinching it between fingers like salt.
Photo 55) Spread a thin layer of mix on top of the seeds. The smaller the seed, the lighter the covering but almost all seeds need a complete cover (primulas and rhododendrons are an exception. These are surface sown – ie not covered). Water carefully. A misting bottle (a well-washed window or shower cleaner bottle with a pump spray) is ideal for fine seed. A watering can with a fine rose to disperse the water is also good. Don’t flood the seeds.
Photo 66) Label the tray. We favour a soft pencil and hard plastic labels which we scrub and reuse for years. Pencil lasts longer than marker pen and is easier to clean for reuse. Precious, fine seed can then be covered with a protective sheet of glass. Stretched plastic can also be used. Until seeds germinate, place the seed trays out of direct sunlight and in good light. It is usually wise to elevate the seed trays away from slugs and snails or cats who think it is a litter box. Check your seed tray daily for moisture levels but do not scratch around looking to see what is happening. When the seeds have germinated, move the tray to sunny conditions and increase the watering as required.

Outdoor Classroom: Layering plants

OLYMPUS DIGITAL CAMERA1) Some plants are difficult to propagate from cuttings, even more so for home gardeners without temperature and moisture controlled conditions. If you are not in a hurry, layering a plant can be a simple way of increasing numbers or of getting a back-up plant for rare or special material which may not be available for sale. This rhododendron has layered naturally where branches lie on the ground.
photo 22) The plant needs to have low growing, flexible branches which reach to the ground. You may wish to try layering plants such as magnolias, rhododendrons, camellias, daphnes or conifers. Most woody plants can be layered over time but it is faster to do easily propagated plants like hydrangeas from cuttings.
photo 33) Select a firm branch or stem which can reach to the ground. It does not matter how old the wood is though young growths from last season may root faster. Remove the leaves from the middle if necessary. Slice a thin layer of bark off the lower side (called making a wound). You can paint the wound with rooting hormone if you have it, but this is not critical.
photo 44) Cultivate a small area of ground beneath the branch or dig a small trench. Peg the branch down so the wound is in contact with the soil. A hoop of wire is ideal for this part of the process. Peg it firmly so it cannot move. Cover the pegged area with up to 10cm of soil. You want to prevent the layered stem from drying out. Leave the branch tip uncovered. Now be patient. It will take a year for easy material and maybe as long as three years for difficult to propagate plants such as many of the rhododendrons.
OLYMPUS DIGITAL CAMERA5) When the layer has formed a reasonable mass of roots, cut it from the parent plant (think of this as cutting the umbilical cord) and either let it grow a little longer where it is or move it to some well cultivated soil – the vegetable garden is often good – so you can take care of it while it develops into a more sturdy plant.
OLYMPUS DIGITAL CAMERA6) You will usually need to stake the plant to train it to grow upwards and to start developing a good shape although you can sometimes plant it on an angle to get the main leader almost vertical.

Gardening 101: Dividing perennials

0011) Clumping perennials can get overcrowded and start to deteriorate over time. Some will stop holding their flowers up well, some can die out from the middle while others just look tired and messy. Some need digging and dividing relatively frequently to stay looking their best. This clump of pulmonaria (unromantically known as lungwort) probably started as a single crown two years ago but grows rapidly.
0022) Dig out the clump, shaking off the soil. If you are not sure what you are doing, hosing off the dirt can make it easier to see the structure of the root system which varies between different plants.
0033) Part the leaves to find the separate sections growing from the centre or crown of the plant. Some plants just pull apart. An old carving knife is helpful and a meat cleaver is good for larger clumps with tough crowns. You can use a spade but it is hard to get accurate cuts. The pulmonaria yielded at least 15 divisions, all of which would grow as separate plants if I wanted that many.
0044) Replant the strongest divisions into soil which is well dug and friable. If you are only lifting and dividing every 10 years or longer, this can be a major task as soils compact over time. If you are doing it more often, it is easy as the soil stays looser. Spread the roots evenly and cover to the same level it was earlier. We like to add compost mulch and then water thoroughly but gently. Removing some leaves reduces the stress on the plant.
0055) These three perennials also benefit from lifting and dividing every few years. From left to right: an aster which just pulls apart into separate sections, mondo grass (ophiopogon) which also pulls apart but sometimes needs the runners snipped, and polyanthus which usually needs to be cut through the crown to ensure that each piece has roots attached.
0066) This patch of stachys (lambs’ ears) was dug and divided three weeks ago and has already recovered well because it is in full growth. Timing is not critical in our mild climate but done in midsummer, care needs to be taken to avoid the roots drying out and plants will need thorough watering for the first week.

First published in the Waikato Times and reprinted here with their permission.

“A good soil, like good food, must not be either too fat, or heavy, or cold, or wet, or dry, or greasy, or hard, or gritty, or raw; it ought to be like bread, like gingerbread, like a cake, like leavened dough; it should crumble, but not break into lumps; under the spade it ought to crack, but not to squelch; it must not make slabs, or blocks, or honeycombs, or dumplings; but, when you turn it over with a full spade, it ought to breathe with pleasure and fall into a fine and puffy tilth. That is a tasty and edible soil, cultured and noble, deep and moist, permeable, breathing and soft – in short, a good soil is like good people, and as is well known there is nothing better in this vale of tears.”

Karel Capek, The Gardener’s Year (1929)