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general plan dry garden
Six years ago the idea for a Dry Garden was launched for a piece of bare land with a surface of approx. 1500 square metres. It was the most brackish part of our 10 hectare (25 acres) property and soil analysis in The Netherlands showed a pH of 8.3 and an organic content of 3 percent next to numerous deficits of nitrogen, phosphorous and diverse trace elements. We choose for the organic and slow way in improving the soil by deminishing the brack and bringing the pH down to 6.8 by adding coarse river sand and plenty of compost in the top 50 cm of the existing (too clayish) soil. After that we soaked everything a few times to get the brack level down (<40ppm; was 200 ppm). And than again mixing compost and gritsand through the top 30 cm of the soil. Considering that it takes approx. 3 years before the new soil (micro-organisms, etc.) is established we waited that long before we made the first trials with some cacti, other succulents and some acacia species including acacia hybrids.
preparation works
This year we made the final decision and two students (Pauline Gillet and Sybille de Cussy) from the landscape university in Blois, France (ENSNP) have been fully engaged in designing the garden and implementing their design in practice.
De Cussy and Gillet knew literally nothing about succulent plants and lack of knowledge often results in an unusual surprising approach.
artist impression of aloe bush
They created a dry garden with 7 spheres (totalling 78 different species, subspecies, etc.); creeping plants, shrubs/trees, rocks, cactus and euphorbia bushes, aloe bush, mixed border, agaves.
rock art in the dry garden
Students of the McGregor Waldorf School were engaged in rock art drawings throughout the garden as part of Land Art Project in South Africa that is initiated by Soekershof.
detail of aloe bush
A PDF-file with plan and plantlist is -free of charge- available for interested landscapers and other interested parties with simular soil ‘problems’. Request e-mail to info -at- soekershof.co.za
This post is “Under continious Construction”.
In the past we have mentioned a few times ’soil’ and ’soil preparation’. See here, there and there.
Every nursery has its own recipes and one may assume that these all work.
In addition to the info provided via the links above:
Succulent plants thrive in a wide range of soils each with their own characteristics. An Aloe plicatillus originate from acid soil (pH <6) near Franschoek in South Africa and and the Gunniopsis glabra originate from a saline flood plain (pH >7.5) in Western Australia.
These differences don’t necessarily mean that these plants don’t grown in different environments.
A good (general) pH of the soil is just below neutral (=pH 7); pH 6.8 is recommended. Soil analysis in the Western Cape is done by Bemlab in Somerset West Do It Yourself pH-meters are not always accurate.
An interesting article about pH is this one. With thanks to Ralph Martin of the south Wales branche of the British Cacti ad succulent Society.
The most important characteristic of the soil is drainage. Especially the top soil must drain freely an excess of water to avoid ‘neck rot’ and also (high temperatures after rainfall) mealy bugs. Ideal is a free draining top layer (10-20cm) of coarse sand or gravel rich soil and a sublayer (10-20 cm) which can accumulate a little bit of water. The characteristics of the sub soil (>30 cm) should be more or less simular to that of the sublayer of the topsoil and is important for deep rooting plants like collumnar cacti. Soil (top- and subsoil alike) may never be waterlogged.
Preferable poor soil (low organic content) but some compost (preferable of horse manure or composted mushroom medium) in sublayer and subsoil is recommended. In some part of South Africa (for example those with brackish/saline soil) an small dose of bonemeal can improve the soil. Fertilisers (even dried chicken manure or ‘bounce back’) improve plant growth but also make the plants extra vunerable for pests and diseases.
No-till
In large scale agricultural operations there is an increasing amount of farmers that implements ‘no-till’ in the cultivation of their crops thus as less as possible disturbing the soil.
Quote from Wikipedia: In no-till farming the soil is left intact and crop residue is left on the field. Therefore, soil layers, and in turn soil biota, are conserved in their natural state. No-tilled fields often have more beneficial insects and annelids[12], a higher microbial content, and a greater amount of soil organic material. Since there is no plowing there is less airborne dust.
No-till increases the amount and variety of wildlife. This is the result of the improved cover because of surface residue and because the field is disturbed less often than conventional fields.
If you know that your soil is suitable don’t dig. 
Preparation limits itself than only to weeding, cleaning and planting unless you planned to make (small) rockery heeps, etc. (see picture).
During Festive Season (school holiday) 2007/2008:
At Soekershof Walkabout, Klaas Voogds West, Robertson, Western Cape, South Africa.
Daily at 11 AM and 3 PM:
Rocking the World; A succulent landscaping project in Robertson.
Designed for all (succulent) gardeners/landscapers who want to know more about the possibilities and impossibilities of waterwise gardening in South Africa with emphasis on the Western Cape. See this and that plus media release below.
R 150.00 pp including picnic and standard program with quest in maze and tour in succulent gardens (see http://soekershof.com).
Duration 3-4 hrs. Only prepaid bookings.
Number of participants per educational limited to approx. 10 PAX.
Subjects:
1) Theoretical basics of landscaping rockeries (soil, composition, creating micro climates)
2) Landscaping a rockery in practice. Interaction between participants and the garden artists of Soekershof.
Discover that waterwise gardening is more labour extensive than generally perceived but also very much rewarding.
Info and bookings: soekershof@lando.co.za Tel: 023-6264134
Rocking the world
Robertson (Western Cape); November 13 2007 – Soekershof Walkabout, Mazes & Botanical Gardens, commenced excavagation works for two rockeries which will the ‘growing ground’ of approx. 1000 succulent species from around the world within two years. These new species are in addition to the 2467 registered different succulent plants in the existing succulent gardens.
The gardens of Soekershof Walkabout distinguish themselves from those of other botanical gardens in South Africa with all plants under the open sky (not under roof or shade cloth) and all plants are organically cultivated without the use of fertilisers and other chemicals. Furthermore is Soekershof Walkabout the only botanical garden in South Africa which is certified by Fair Trade in Tourism in South Africa (http://www.fairtourismsa.org.za/).
Both rockeries are near the entrance; one will be the ‘growing ground’ of caudiciform plants (f.e. ‘bottle trees’, including several baobab species, from Australia, Madagascar and Southern Africa) and the other one will mainly consist of American succulent plants such as cacti, yuccas and agaves next to Brazilian ceiba trees (Choriosa speciosa). Most plants of the new collection are home grown from seeds and hardly or not on display elsewhere in South Africa.
The investment in the new rockeries is the first phase of a three year program during which all ‘gaps’ in the existing landscape of 10 hectares will be filled with different sphere gardens. In the beginning of next year excavagation works are scheduled for a very formal layout of sample gardens for the own nursery customers and the extension of the Langeberg Garden (in fact a maze without dead ends and home grown indigenous trees and shrubs).
Since the official opening in December 2002 Soekershof Walkabout is increasingly attracting (amateur) horticulturists, garden societies, botanists, etc. from around the globe. Locally Soekershof Walkabout is mainly known for its Klaas Voogds Maze which is regarded as the ‘largest hedge maze in the world’.
Walk
Wonder
and be
Inspired!
Soekershof Walkabout
Mazes & Botanical Gardens
Primary Unusual Destination
Certified by Fair Trade in Tourism in South Africa
Klaas Voogds West, P.O. Box 291, Robertson 6705, South Africa
Tel: +27 (0)23 626 4134
Skype: soekershof
E-mail: soekershof@lando.co.za
Website: http://www.soekershof.com
Blogsite: http://soekershofwalkabout.blogspot.com/
Soekershof Science: http://soekershof.wordpress.com
Dutch: http://www.dagboek.iblog.co.za
http://www.travelpod.com/members/soekershof
Mission statement:
Soekershof Walkabout is a sacred enterprise, based on an appreciation of nature, humor, play, creation, expression and respect for the land, and the growth and development of the people and plants that participate -employees and visitors alike.
Soekershof Walkabout is a personal event which is simply described as the “Largest Hedge-Maze in the world” and/or “a garden with more than 2400 different succulents from all over the world under the open sky”.
But Soekershof IS more than that.
The original concept goes beyond all prejudice perceptions.
Walk, Wonder and be Inspired!!!
Just let it happen and take your time; a few hours at least.
Experiencing Soekershof Walkabout is, globally, a unique and hugely entertaining exercise for Body, Mind and Spirit; not to be missed.
Daily Tours: 11 AM and 3 PM (sharp!!!)
See website for more details.
Towards the end of the South African winter it’s not a bad idea to provide the Spring growth of plants with an organic ‘headstart’.
In Wikipedia you can find a few articles about organic soil improvers.
Look under bone meal and sea weed. Both stimulate the root growth. Good healty roots are the foundation for a healthy growth of the plant.
What’s not mentioned in Wikipedia is the use of composted horse manure; also rich is phosporous like bone meal but not the risk of contamination with lead and so on as some bone meal products.
Sea weed is available in South African shops as SeaGro and in large quatities at agricultural suppliers as Kelpak. It’s a true South African product (Made in Simonstown). Just spray it on plants and soil at the end of August and once more in mid-October. Bone meal: a little hand full around every plant and slightly cultivate it in the soil. Only once a year around this time. And don’t believe what the manufacturor writes on the package (“every six weeks”). Plants can get killed due to an overload.
Composted horse manure: Spread between the plants and with a bit of cultivating mix it with the top soil. Here we are glad with a horse keeping neighbour. Thoroughbreed horses with honest natural food without hormones and other ‘boasters’.
One golden rule: Too much is too much. Relativily small quantities are the best. Don’t make it too easy for plants (they get vunerable for diseases and pests). Life is hard; should also be for plants. That makes them strong.
Keep on talking with your plants.
The Euphorbiaceae family consists of around 300 genera and about 7500 species of which approximately 870 are succulents. About 50 genera and 487 species are native to Southern Africa including Madagascar. These figures excludes the numerous varieties and hybrids such as those of the E. milii and E. pulcherrima (pointsettia).
The International Euphorbia Society covers the whole spectrum of this plant family including the non-succulent ones.
General information about succulent Euphorbias can be found here. The most valuable Internet source (including photo’s and cultivation info) however can be sourced at this site.
Euphorbias are named after the Greek surgeon Euphorbus.
Most of the succulent species of the Euphorbia are easy to grow in most parts of South Africa provided that there is sufficient drainage and the humidity is low. High humidity causes mildew and, combined with high temperatures, mealy bugs. Good drainage prevents Euphorbias from root mealy bugs and root rot (caused by fusarium fungus). Plant Euphorbias preferable on a slope and in well drained soil. Large collumnar plants always surrounded by rocks. In general Euphorbias are less susceptible to diseases than other succulent families. In the past we already submitted something about pest and disease control the green way . See also this contribution and these ones.
Propagation can be done by sowing and by means of cuttings.
Some Euphorbia species hybridise easy and to prevent this as much as possible is hand-pollination with a brush. Always plant two of more plants of the same specie next to each other.
As for cuttings: cuttings of succulent Euphorbias can best be taken towards the end of the dormant season. We normally take them towards the end of the South African Summer (February-March) and always in the early morning but preferable in the late afternoon. Keep the cuttings under a running tab until the cutting stops ‘bleeding’ latex. This milky sap is poisonous (always wash your hand afterwards and or wear protective clothing). Let the cuttings dry in a dry shady area with good ventilation for at least 3 to 4 days before planting them.
Many South Africans assume that a waterwise garden means a “low maintenance garden”.
In our daily practice at Soekershof Walkabout we regulary have discussions with nursery customers about the importance of maintenance. Weeding and ‘communicating’ with plants is an ongoing process; especially in the Winter rainfall area as the Western Cape. Last weekend we had some showers and the weather forecasting shows us raising temperatures for the next days. For our gardeners the sign to aerate the soil around the succulents with a cultivator. This let the moisture evaporate faster and keeps the neck (neckrot) dry. Another good reason to do so is that with the next rainfall the surplus of water will drain away easier. While cultivating they always feel the neck just under the surface just to make sure that these are still fleshy and not soft. Cultivating and weeding go hand in hand. Partly cultivating is weed prevention because the soil dries out faster and weed seeds generally don’t germinate in dry soil.
This group of highly succulent, more or less leafless plants belongs to the family Apocynaceae. Found exclusively in the Old World, they are widely distributed over the drier parts from the Southern-most tip of Africa to the southern shores of Europe and eastwards to Arabia, India and Myanmar. Of the roughly 330 known species, 182 occur in Southern Africa, and all but a handful of these are endemic to this region.
Asclepiadaceae is a plant family which differs from others by having a very complex sexual apparatus and a complicated pollination procedure. They are easyly recognisable by five-lobed flowers. The lobes are joined together at the base of flower (corolla).
There are about 2000 species of Asclepiadaceae split into some 300 genera, of which about half are succulent. The succulent ones are of interest, especially the group named stapeliads. Their flowers are miraculous. I have read somewhere: “Orchids of the Succulent world”/ The flowers of stapeliads have one flaw only. Most of them don’t have a pleasant smell.
Asclepiads grow worldwide, from jungles of Indonesia to deserts and steppes of Africa while stapeliads grow only in the old world. There are some representatives in Europe, too, in Southern Italy and Spain. Most of them are from dry regions of South, East and North Africa, Arabian peninsula and some even from India, Sri Lanka, Myanmar (Burma) and Nepal.
Most Asclepiads enjoy warm conditions, and appreciate regular application of water in hot Summer weather providing that the plants are in their growth phase. For some of the more difficult Asclepiads, heat is a requirement and watering should be more circumspect. At Soekershof Walkabout we always use rain water, and tend to water over the top of most plants – after all that is how it happens in habitat. However, many growers prefer to water plants from the bottom (simulating drier conditions where the roots seek underground moisture), and a careful approach to watering is essential for difficult or rare plants. It is a good idea to allow the soil to dry out between waterings, and if the weather goes cold in the middle of the summer, then stop watering. Much of the reputation that Asclepiads have for rotting unexpectedly is probably related to watering plants too early in the year while still dormant, or when the weather is uncertain, or to attack by other pests such as root mealy bug, the damage from which allows disease into the tissues. Indoors Asclepiads seem to do best in very free-draining gritty compost which helps the compost to dry out between watering. Peat-based composts, with lots of sharp sand and fine grit works well, but peat also encourages root-mealy bug.Always remove dead plant material (dead flowers, leaves, stems) from your growing space, as otherwise in damp weather it will become colonised by fungi and rapidly become a source of spores, which may in turn infect your asclepiads.
If a plant that was growing well suddenly goes into a decline, suspect root-mealy bug. This pest destroys the roots, preventing proper uptake of water, so the plant looks under-watered even though it is sitting on soggy compost. Probably the damage also helps fungi to enter the tissues, and the next stage is a rotten plant.
Ordinary mealy bugs are also a major problem with Asclepiads, and are difficult to eliminate from crevices between the stems. Mealy bugs can be spread through a collection by the wandering vegetative growth of tuber-forming Ceropegias. Scale insects are said to be a major pest of Asclepiads in some climates.It is a good idea to take cuttings from suspect plants that are not thriving, clean off obvious infestation and start off some new plants in case the original can not be saved.
Here we replant most of the asclepiads (especially Stapelia-species) every one of two years on a new location. This also prevents rot caused by soil related fungi, etc.
Propagation
Many Asclepiads are readily grown from seed, and some people grow plants of the faster growing species to flowering size from seed each year, thus avoiding problems of overwintering. However, the seed of many species (e.g. Stapelia sp.) has a limited life expectancy, and should be sown fresh. Those species with fleshy stems are easily propagated from portions of the plant laid flat on a gritty potting mixture, when they will produce roots from the underside of the stems. Planting stem cuttings vertically seems generally less successful (an exception is the vine-like Ceropegia species e.g. C. radicans), and the portion of plant embedded in the compost is prone to rot rather than root. Tuber-forming Cereopegias can be propagated from small tubers formed at joints in the thin stems. Regular propagation of plants with a few cuttings seems to be the best insurance against loss of the main plant.
Internet literature:
Today something about (re-)planting the big (columnar) cacti and euphorbias.
It’s simple: Plant it in such a manor that it can resist a strong wind without ‘bending over’ ending on the ground. And that you prevent the plant from neck-rot.
Make a hole deep and wide enough; better a bit too deep and too wide. Make a soil mix as described in the contribution about cuttings.
Loosen the soil on the bottom of the hole and mix it with the self-prepared soil.
Top this with a layer of approx. 5 cm self-prepared soil.
Place carefully the plant in the hole and spread the roots. Top the roots with a layer of 10-15 cm of self-prepared soil.
Put large rocks in the hole around the plant with a distance of 5 to 10 cm from the stem. And that their tips stick a little bit above ground-level.
Put the rest of the self-prepared soil in such a way that you compact the soil between plant and rocks. And that you shape a small heep around the stem ending at the outer-side of the rocks. This will let the surplus of rain water drain away from the plant keeping the neck as dry as possible.
This method has the ‘disadvantage’ that you have to plant deeper as they were at the nursery or in the pots. This extra depth means a year (or more) of growth before the plant, above ground-level, is as high again as you bought it.
The big advantage of this general method is, provided you did it right, that the columnar cactus or euphorbia will stand as a rock in the wind.
We learned this method in a natural way in one of our gardens. When this first cactus garden in South Africa was planted almost a 100 years ago Marthinus Malherbe planted all the collumnar cacti and euphorbias that way. During the restoration of this garden we had to take (after 24 years of neglect) almost all succulents out and remove the contaminated soil. Removing the big ones was quite a job for their root-system was covered with huge rocks. But not one columnar cactus or euphorbia ’tipped’ in 90 years despite the heavy winds every now and than.
Whatever you do to avoid it; sooner or later there is a plant with rot. We recently experienced this with a quiver tree which prosphered in one of the gardens for more than 6 years. And suddenly, at the brink of the South African Autumn, the tree let us know that there was such a ’soft feeling’ at its neck. Taking the soil away we discovered that part of the neck just started to rot. We took it out (almost 150 kilogram) and laid it to rest in the barn. The past week we’ve taken the rot parts away and let dry for the next few months until Spring before we replant it. Luckely for both, us and the tree, some of the roots were not attached. In October we will replant the almost 3 metre high tree on a somewhat higher spot and we’ll cover the neck and the top part of the roots with coarse sand for better drainage.
Rot can never be avoided in full but some measurements can avoid at least 90 percent of the misery.
It starts with buying your succulents.
And plant them in the right soil; more or less the mix as described in one of the contributions last month.
The top layer of the soil should be 30 to 50 cm deep and the subsoil should be able to drain the surplus of water sufficiently even after a heavy rainfall.
Keep the soil around the plants free of weeds.
Plant vunerable succulents on a small sandy heep (5-10 cm high).
After (heavy) rainfall aerate the soil around the plant (loosening the top few centimetres).
But still than, as in our case with a very valuable quiver tree, rot can strike suddenly.
Neck-rot is caused by phytophthora. This is a fungus which also occurs in potatoes and caused the Irish famines in the 19th century and with that the Irish influx in the America’s.
There is not much what you can do in a natural way other than taking the affected plant out and cut the rot part out. If you discover the disease in a late stage it can be too late for the whole plant. The only thing left is to cut the plant off above the neck and let the stem dry first and than root again as a cutting.
ALWAYS remove the soil around the affected plant (it might be contaminated) and do not add the attached parts (or whole plants) to the compost heep for it will spread the disease to all the places where you spread the compost.
Connie Krochmal, the cactus and succulent editor of Bella Online, recently wrote an informative article about all kinds of (rot-related) diseases in cacti and other succulents such as fusarium, botrytus and (powdery) mildew.
At last but not at least: communicate with your plants. They will tell you about their needs, their shortcomings, their symptoms of ‘illness’. Talk with them with your eyes, your fingers, you nose and also with your mouth. It helps. Really.
The genus name Aloe is derived from the Arabic, alloch and translated as allal in Greek and Hebrew, literally meaning bitter or bitter sap which is descriptive of Aloe sap. The genus Aloe belong to the family Asphodelaceae to which also other succulent genera such as Haworthia and Gasteria. A widely spread misunderstanding is that also the Agave and related American genera belong to the same famly. These belong to the family of the Agavaceae. Some Aloe species (f.e. A. Ferox, A. Barbados and A. Socotrine) are valued for their medical properties. There is however a large number of medical claims which are not scientifically proven up to date or are proven to be false. The globally best known Aloe is the Aloe barbadensis (better known under the previous botanical name Aloe vera). The Aloe barbadensis is commercially cultivated in the USA, Australia and India. In Maharashtra, Madhya Pradesh, and Gujarat, India, Aloe vera is raised as an organic. The crop is ready for harvest after 18 months from sowing. The average yield for organically grown aloe is approximately 12 t/ha.
Soil
A slightly alkaline (up to pH 8.5) sandy loam soil is the most ideal for most Aloes but some prefer slight acidic soil (pH 5.5-6.5) such as A. mitriformis (A. perfoliata) and A. plicatilis. It is normally propagated through root suckers or by cuttings of the new growth. Because Aloe plants consist of 95% water, they are extremely frost tender. If they are grown outdoors in warm climates, they should be planted in full sun, or light shade. The soil should be moderately fertile, and fast draining. Established plants will survive a drought quite well, but for the benefit of the plant, water should be provided.
All known garden pests can be kept to a minimum by simply ensuring optimal growing conditions and a good selection of plants that attract wildlife to your garden. In principle a garden is always un-natural. One of the challenges of organic gardening is to make use of nature in order to strive towards an ecological balance. For our and your dissapointment: even nature is never in balance. There are many ’surprises’ every year but without ‘ecological measurements’ these can go a bit out of control. A daily ‘inspection’ walk in the garden -preferable early morning or late afternoon- helps the gardener to foresee ‘threatening’ pests and diseases and making the right decisions towards preventive measurements.
Most common pests/diseases in aloes are aphids, scale insects and cancer.
For scale insects the best results are obtained by physically removing scale using a cloth.
Occasional aphids on flower clusters and scale insects on leaves. These are relatively easy to control with water (high pressure) of, even better, preventive with a tea of garlic. Aphids are ‘farmed’ by ants. The ants regard aphids as their ‘milk cows’. Keeping ants away, two rings (10 cm or 4 inches space between them) of chalk powder on soil around aloes, minimalise the number of ants and aphids.
Cancer: Caused by aloe-cancer mite. This mite lives inside the plant and is the carrier of the virus and cause the cells to multiply and form ugly weird growths. Cut out the affected part of the plant and let it dry. General info about pest control and pest and disease prevention can be read elsewhere in this blog
Propagating
Propagating is best done via cuttings. Sowing is also possible but bear in mind that Aloes hybridize easily.
Southern Africa is home to a few hundred Aloe species. Two of our favorites are the Aloe perfoliata and the Aloe polyphylla.
Growing A. perfoliata is very easy. The best results are achieved by simply making stem cuttings. Allow cuttings to dry for a few days and insert into river sand and keep moist. The roots appear after about two weeks. Seeds must be sown as fresh as possible. When kept too long they are parasitized by small crawling insects. The best time for sowing would be in the winter, June to July. Use coarse river sand and cover seeds lightly, then keep moist. It is advisable to treat seeds with a tea of khaki-bush, as seedlings are prone to damping off, a fungus that eventually kills the young plants. Simply add tea to the soil. After germination, when plants are about 20 to 30 mm, plant over using a sandy-loam medium. If you have a garden with clay soil, use some bone meal to break up and nourish the soil. Mature plants in the garden may from time to time be subjected to attack from scale insects and aphids.
Aloe polyphylla originates from high, relatively cold, altitudes in Lesotho. It is a very difficult plant to cultivate in the open in the Western Cape. It’s main requirement is well-drained soil. It performs best when planted on a slope (or planted up at a slight angle so water does not collect in the spiral), where it can enjoy sun, or part (afternoon-) shade in the hottest areas. It also does well in pots. Water requirements depend on soil and weather. They are generally suited to low water, but prosper with some summer water.
Information about South African Aloe species can be obtained via one of the websites of the National Biodiversity Institute. This site contains a wealth of info of many indigenous plants including succulents.
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