Cultivation

Like all cacti in cultivation Ferocactus need plenty of light, watering in the growing period, repotting (especially in the early years of their growth), protection from frost and excessive wetting in less kind climates, and provision of sufficient nutrients to enable growth to be slowly but steadily achieved. The usual precautions against attack from the various pests also need to be taken, although they are themselves well equipped to resist attack from domestic animals, including their owners. What follows is a guide mainly directed to growers in the United Kingdom; readers in other countries will hopefully have developed their own ways of keeping their plants in their particular climatic conditions.

Light

Light is, as with most cacti, essential for healthy growth, and in the summer months these plants more than many cacti benefit from being in the open air to maximize the amount of sunlight they receive. Certainly in habitat in the southern USA and Mexico they are sun-seeking, growing out in the open and taking all the sunshine they get with equanimity. In the UK this largely solves the problem of sooty mould forming on the sugary secretion these plants make from glands above the areoles, of which more below. If kept continuously in a glasshouse shading is unnecessary, but air circulation in sunny weather should be maintained to prevent the plants scorching through too much heat in confined conditions, especially if they are close to theglass. From early spring onwards it is important that the plants receive the maximum light. To this end the glass should be cleaned andany winter protection by way of plastic should be removed.

Watering

Watering depends on the individual grower's conditions where the plants are kept, but should broadly follow that recommended for most other cacti. This means none in the cold winter months, to allow the plants to indulge in the rest period for which they are well adapted, and to avoid any inclination to grow when light is at a low level, which will result in soft, uncharacteristic growth and weak spine development, if not their demise from the combination of low temperatures and dampness.

One good watering on the first really sunny day in early spring will wake the plants up and get the hair roots growing to swell the plants and let them know that the time has come for growth. Allow the plants to dry out before watering again - the time this takes will depend on the size of pots the individual plants are in, varying from a week or two for pots below about 10cm in diameter, to as much as a month for larger pots. As the spring gives way to summer watering can be increased, and once danger of night frost is past the plants may be stood outside the glasshouse. Protection will be necessary from slugs and snails, which will relish this exotic change of diet, spines or not. The wool on the areoles, when plants are kept outside, does tend to lose its colour and become greyish and, if there is excessive rain (not uncommon in the UK), nutrients are quickly leached from the pots. In this case, reponing in the winter following is advised. As summer comes to an end, reduce the frequency of watering, and bring the plants inside the glasshouse as soon as there is danger of frost. Water should be withheld from large pots (20cm or more) from the end of September to give them time to dry off completely before the late autumn, smaller plants can be watered until about the end of October.

Feeding

Fertilizers with a high potash content may be used during the growing period at full strength recommended (any fertilizer recommended for tomatoes, chrysanthemums or roses is fine); this will promote good growth of spines as well as the plants, and will encourage flowering. It makes sense to give the fertilizer mixture a day or two after a general watering when the plants' roots are in active growth, so that the maximum uptake of the nutrients is achieved; this secondary fertilizer dosing can then be less in quantity as well as more effective

Compost

The potting medium is a vexed subject, and if the reader has a mixture which suits his plants then the advice is stick to it, and experiment carefully with any changes adopted. A compost based on soil, preferably with a clay-like appearance seems to give good results, with the addition of small particle grit to open the mixture and facilitate drainage; two parts of compost to one of grit seems to be about right.

Repotting

Moving the plants on into the next sized pot in the first few years will encourage them to develop quickly. Even when they are in pots exceeding 15cm they will benefit from such repotting every 2 or 3 years as the soil will have exhausted any nutrients, and the humus content will have broken down and reduced the ability to hold water, to the detriment of the plant. The common sense time to repat seems to be, as for most plants, when they are resting in the winter, so that any damage to the roots is given time to callus before being in contact with water in the soil. Use a dryish mixture when repotting, and withhold water for at least 2 or 3 weeks afterwards. Topdressing the compost with a layer of grit not only improves the appearance of the potted plant but slows down the transpiration of water from the compost during the growing period as well as preventing mud splashes on the plants when watering, or the formation of mosses and algae on the surface. As with most very spiny plants, and this certainly applies to all species of Ferocactus, we have found that a thick cushion of several layers of either crumpled newspaper or, better, bubble polythene on the work surface enables carefully laying the plant down sideways on this cushion, and then tipping out the plant sideways from the pot byknocking the pot away with sharp taps on the rim. The rootball can then be grasped to lift the plant into position in the new pot, which should have sufficient depth of compost in the bottom already to keep the plant more or less at its previous level, followed by carefully and gently tamping fresh compost around the rootball. In this way neither the plant's spines are damaged, nor, if you are careful, do you have to come into contact with the spines.

Temperature

Most species will be happy with a minimum winter temperature of 5°C, but some will do better and be less likely to suffer cold damage if lOOC can be provided. This particularly seems to apply to F. latispinus, F. recurvus, F. robustus and F.flavovirens. Having said that, there are growers in the UK who provide no heat, drying the plants off at the latest by mid-September, and their plants seem not to suffer at all, but in these circumstances it is advisable to keep the air moving in the glasshouse by means of a fan.

Pests

The usual pests of cacti, mealy bug and red spider mite, will attack your Ferocactus plants given a chance. A bad infestation of either is best treated with a systemic insecticide, thoroughly drenching the plants to ensure maximum effect. But if your collection is relatively clean, and only slightly affected by an advance party of either pest, then a contact insecticide will keep them at bay. Constant inspection for early signs of attack is advisable to avert serious damage by these insidious pests. If using any insecticide do remember that they are dangerous chemicals, and full precautions to avoid skin contact or inhalation of the vapour from them should be rigorously followed. Leave the glasshouse for several hours at least after their use, and wash face andhands and any other exposed skin.

Predators are fashionable at present for pest control, but that is all they will do, control them, they do not usually eradicate them completely and have the disadvantage of needing for their survival warmer conditions in the winter than usually economically possible to provide.

Sooty mould

Most species of Ferocactus bear a gland at the top of each areole, which exudes nectar. If the nectar is allowed to remain on the plant a mould will form, the fruiting parts of which form an unsightly black coating around the areole, as well as the spines and body of the plant, wherever the nectar is present, spoiling the appearance of the plant. Once formed this mould is very difficult to remove. One way of prevention is to spray regularly with water (preferably rainwater as this leaves no residue), so that the nectar is constantly washed away as fast as it is produced.

Another method of combating the formation of sooty mould is to encourage sufficient ants, bees, hover-flies or wasps to the glasshouse, which all love to sup the nectar. Unfortunately this marshalling of insect help is not very easy to achieve, and there are some disadvantages in introducing the most effective of these, the ants.

In the summer months the plants can with some advantage be placed outside, so that they are more accessible to these beneficial insects and subject to occasional washing from our inevitable summer showers, but it is left to the reader to decide which method could be most effective in his or her situation bearing in mind the remarks above in the paragraph about watering. Plants placed outside in the UK are subject to scorch unless gradually acclimatized to the extra light, and a position giving some dappled shade for at least part of the day is advisable.

Finally let us reiterate the advice given at the beginning of this chapter: if you have found methods of growing your plants which work carry on using them.

Map of distribution area

Key to states of the U.S.A.

I. California 2. Nevada 3. Utah 4. Colorado 5. Arizona 6. New Mexico 7. Texas 8. Oklahoma

Key to Mexican states

Baja California Baja California Sur Sonora Chihuahua Coahuila Sinaloa Durango Nuevo Leon Tamaulipas 18. Zacatecas 19. Nayarit 20. San Luis Potosi 21. Aguascalientes 22. Jalisco 23. Guanajuato 24. Queretaro 25. Hidalgo 26. Veracruz 27. Colima 28. Michoacan 29. Mexico 30. Tlaxcala 31. Puebla 32. Morelos 33. Guerrero 34. Oaxaca 35. Chiapas 36. Tabasco 37. Yucatan 39. Quintana Roo

Geography and Distribution

As well as the more obvious tall, columnar cacti, Ferocactus species throughout their distribution in the southern United States and in Mexico are often among the most prominent cacti in the wild, and are often indicators of a kindly cactus habitat, where other, smaller genera might be found.

They are mostly found in rocky terrain, although some do occur also on the flat. They are in general not high altitude plants, seeming to prefer the lower slopes, rather than upper reaches of the mountains where they occur, although some are found at quite high altitudes, often as outliers of more abundant occurrence at lower levels. Alfred Lau's highest recorded altitude for any species is 2, 100m - F pilosus in Coahuila, closely followed by F alamosanus subsp. reppenhagenii, at 1,500 to 2,OOOm, most other species recorded· at altitudes from sea level to about 1,000m. Werner Reppenhagen records F latispinus at up to 2,500m in Hidalgo and F recurvus in Puebla at the same altitude. F occurs also at 2,300m in San Luis POtOSI and in Mexico D.E, and at 2,400m in Guanajuato, the same species and F histrix at up to 2, 100m in Queretaro, F histrix and F echidne and F glaucescens in Hidalgo at 1,500 to 1,900m; also F histrix in Zacatecas at nearly 2,000m. He also records F robustus at 2,1 OOm in Puebla, F flavovirens in Puebla at 1,900m, F recurvus in Oaxaca at 1,600m, F alamosanus subsp. reppenhagenii at 2,000m to 2,300m in Michoacan and in Colima at 1,200m, F pilosus in Durango at 1,700m, and F macrodiscus at 2,300m in Oaxaca. Most other species occur from almost sea-level to about 1,500m.

The maps accompanying each taxon in the chapter 'Species commentary' are based on reliable reported localities for these plants and the authors' own observations. They give an approximate idea of the spread of each taxon, and are by no means precise. (Altitudes arc those listed by Alfred Lau and Werner Reppenhagen, and recorded by Nigel Taylor) USA

ARIZONA: F cylindraceus (60-600m), F cylindraceus subsp. eastwoodiae (390-1, 140m), F cylindraceus subsp. lecontei (300-1 ,500m), F emoryi. F wislizeni

CALIFORNIA: f: cylindraceus (60-600m), F cylindraceus subsp. lecontei (300-1 ,SOOm), F viridescens

NEVADA: F cylindraceus subsp. lecontei (300-1 ,500m)

NEW MEXICO: F hamatacanthus, F wislizeni

TEXAS: F hamatacanthlls, F hamatacanthus subsp. sinuatus, F wislizeni

UTAH: F cylindraceliS subsp. lecontei

MEXICO

AGUASCALIENTES: F histrix (2, 100m), F latispinus

BAJA CALIFORNIA and BAJA CALIFORNIA SUR mainland: F chrysacanthus subsp. (1200m), F cylindraceus (300m), F cylindraceus subsp. tortulispinus (600m), F emoryi subsp. rectispinus (1-1 ,600m), F fordii (1-50m), F .f{Jrdii subsp. borealis (I-100m) F gracilis (20300m), F gracilis subsp. coloratlls (IO-IOOm), F peninsulae (I 00-400m), F peninsulae subsp. santamaria (I-10m), F peninslilae subsp. townsendianus (lOO-450m), F viridescens (l0-400m), F viridescens subsp. liuoralis (800-1 ,000m)

BAJA CALIFORNIA islands: F chrysacanthus (1-500m), F chrysacanthus subsp. grandij70rus (I-200m), F diguetii (1O-300m), F fordii (I-10m), F gracilis subsp. gatesii (I-150m), F johnstonianus (I-300m), F peninsulae subsp. townsendianus, F wislizeni subsp. tiburonensis (l0-200m)

CAMPECHE: none recorded

CHIAPAS: none recorded

CHIHUAHUA: F alamosanus, F hamatacanthus (I,500m), F pottsii (1,150-1 ,200m), F wislizeni (1,000-1,750m)

COAHUILA: F. hamatacanthus (650-1,900m), F. hamatacanthus subsp. sinuatus, F. pilosus (1,250-2, 100m)

COLIMA: F. alamosanus subsp. reppenhagenii (1,2002,000m)

DURANGO: F. hamatacanthus (l,650m), F. histrix, F. latispinus, F. pilosus (1,700m), F pottsii, F. wislizeni subsp. herrerae (to l,4oom)

GUANAJUATO: F. echidne, F. histrix (2,000-2,300m), F. latispinus (l,800-2,400m), F. macrodiscus subsp. septentrionalis (2,000-2,350m)

GUERRERO: none recorded

HIDALGO: F. echidne (l,300-1,700m), F. glaucescens (l,450-2,3OOm), F. histrix (I,5OO-2,000m), F. latispinus (1,500-2,500m)

JALISCO: F. histrix (2, 100m), F. latispinus

MEXICO: F. latispinus

SAN LUIS POTOSI: F. echidne (l,100-1,600m), F. glaucescens (I,600m), F. hamatacanthus (I,550-2,000m), F. hamatacanthus, F. histrix (1 ,550-2,300m), F. latispinus (l,550-2,3OOm), F. macrodiscus subsp. septentrionalis, F. pilosus (l,200-2,100m)

SINALOA: F. alamosanus, F. emoryi (1-900m), F. pottsii, F. schwarzii (30-300m), F. wislizeni, F. wislizeni subsp. herrerae (30-200m)

SONORA: F. alamosanus (350-1 ,300m), F. cylindraceus (I-200m), F. cyLindraceus subsp. Lecontei, F. emoryi (5-3OOm), F. pottsii (I,800m), F. wislizeni (40-1 OOm), F. wislizeni subsp. herrerae (1 0-650m)

TABASCO: none recorded

TAMAULIPAS: F. echidne (500-2,000m), F. hamatacanthus (1 ,300m), F. hamatacanthus subsp. sinuatus (1,2oo-I,300m), F. pilosus

TLAXCALA: none recorded

MEXICO DF: F. latispinus (2,300-2,450m)

VERACRUZ: F. haematacanthus (2,000m)

MICHOACA.N: F. aLamosanus subsp. reppenhagenii (2,OOO-2,300m), F. Latispinus, F. lindsayi (250-300m) YUCATAN: none recorded

MORELOS: F. Latispinus

NAYARIT: none recorded ZACATECAS: F. hamatacanthus (2,150m), F. histrix (I,950-2,250m), F. Latispinus (2,250-2,300m), F. pilosus (2,400m)

NUEVO LE6N: F. echidne, F. hamatacanthus (501,450m), F. hamatacanthus subsp. sinuatus (350384m), F. pilosus (1,300-1,900m)

OAXACA: F. aLamosanus subsp. reppenhagenii (1,500m), F. Jlavovirens, F. latispinus (I ,800m), F. macrodiscus (l,700-2,500m), F. recurvus (5002,440m), F. recurvus subsp. greenwoodii (1 ,400m), F. robustus

PUEBLA: F. Jlavovirens (1,600-1 ,900m), F. haematacanthus (I ,750m), F. hamatacanthus (2,300m), F. Latispinus, F. macrodiscus subsp macrodiscus (?), F. recurvus (l, 100-2,5OOm), F. robustus (l ,500-2, 100m)

QUERETARO: F. echidne (700-1,400m), F. gLaucescens (I,000-1,800m), F. histrix (I,200-2,250m), F. latispinus (l ,800-2, 100m), F. macrodiscus subsp. septentrionalis