Cacti

Ask any cactus collector about growing cacti outside and the reply is normally a short 'You can't'.  Well, knickers, you can.  One of the biggest problems is keeping up with the changes in nomenclature.  Here is a selection of those that I know will, have been told should, or believe may, overwinter outside.  Few pics at the moment, but as my collecting, planting and experimenting progresses there will be loads !  Link here to a very long list of suspects with no descriptions. 

Autumn 2000:  The update for this year was that they all weathered a mild but extremely wet winter brilliantly - they just grew a lot!

ACANTHOCALYCIUM

A small globular cactus - eventually forming a small column 15cm across by 50cm high.  Worth trying. ( 1999 )

CEREUS

Tall, branched columnar cacti that are very fast growing.  There are loads of species, many almost identical leading to much confusion over naming in the houseplant trade.

A bit 'iffy' - won't take any great depth of cold - also variable and misnamed nearly everywhere.  I have heard reports that when acclimatised in a favourable spot this will survive -10C but it is cheap, readily available from most cactus nurseries and fast growing so definitely worth the risk.  At time of writing mine has taken -5°C ok - well a bit spotted... (1999) 

ECHINOCEREUS

These are generally small globular cacti that cluster into small colonies - some eventually elongate into small columns.  Some species are extremely cold tolerant indeed and have a track record in the US for growing in wet winter conditions.

Variable - typically small, clustering with greenish yellow flowers.  Hardy. (1999)

An extremely variable species with many subspecies and varieties, this is generally another small globular cactus that clusters and, typically, gorgeous pink flowers.  Some forms very hardy. 

Another very variable plant - some subspecies are nearly devoid of spines, others and very spiny indeed.  Nearly all are very hardy. (1999)

Superficially resembles E. chloranthus.  Hardy.  (1999)

ECHINOPSIS

Variable species - typically a small clustering cactus with attractive yellow flowers.  Quite hardy (1999)

Another one often seen as lobivia / echinopsis / trichocereus, it forms a trailing column maybe 60cm long and 3cm across, with red/orange or yellow flowers.  Quite hardy.

FEROCACTUS

The barrel cacti are conspicuous features of the deserts of the southwestern states of the US.  In these conditions they generally grow into huge plants, sometimes 3m high and 60cm across, with very long and often attractively coloured spines.  Some species are given the common name 'horse crippler' ( or 'Mother-in-Law's armchair' - true ! )  which graphically suggests the nature of these spines.  It is possible that some may grow outdoors here, maybe with winter rain protection. 

I have been told this is the best bet for outdoors of the ferocacti, it should form in interesting large blob on the cactus patch eventually reaching 50cm across and even getting head high !

A variable plant, some most forms have very attractive short red spines - some have additional longer white spines - and in old age can reach over 2m and 50cm diameter.  May be worth trying here. (1999)

Again a variable plant - some collections are more likely to succeed than others - those from Utah or Arizona are preferable to those form, say Texas or Mexico.  (1999)

GYMNOCALYCIUM

Small globular cacti from South America, some of which cluster, mostly solitary, many should prove hardy.  I am planting out many this season to try.

A small, solitary globular cactus with variable flower colour.  Should be hardy.

A small, clustering globular cactus with pinky-white flowers.  Should be hardy. 

Variable plant - a little bigger then the others with whitish flowers and, in some plants, very dark almost black stems.  Should be hardy.

MAIHUENIA

Two species, distant cousins of opuntia, that have fleshy wrinkled stems, fleshy persistent leaves and long white spines.  Eventually both branch extensively and form large domed colonies.  The major difference, apart from the fact that M. patagonica is much rarer in cultivation, is the flower colour - yellow in M. poepegii, white in M. patagonica.  Both are completely hardy and actually enjoy some rain.

OPUNTIA

A colossal genus of jointed cacti - the major distinction is whether these joints are flattened and oval or round in shape - the padded opuntias; or cylindrical often with indistinct joints - the chollas.  Some are very small, staying close to the ground, others will make large shrubs; overall an extremely varied genus from which the greatest choice of hardy cacti can be made.  As with cacti in general, naming is a serious problem ; I have steered clear of listing synonyms as it is a minefield - not even 'experts' that spend their lives wandering the deserts of the southwest can agree on what exactly is what - as plants of one species growing in one locale can look identical to plants of another species growing elsewhere.

In hot climates some of these plants have become weeds that are illegal to plant - here they behave more gently.  Several have proved themselves to be completely at home in the British climate, many more probably are; it is just trying to find the best plants.  A warning.  It hurts an awful lot when one of the large spines sticks into you - often they are barbed on the tip and painful to remove.  That is NOTHING compared to the misery of the small hair like spines, called glochids, that lie in wait beneath.  You can barely see them - especially if your eyes are like mine - but you will certainly feel them.   BEWARE and always handle with extreme care. 

Alas not one of the hardiest but one of the most attractive - large, fat purple tinted pads with no spines - common name is beavertail cactus and that is really what it looks like.  Beware the glochids - they seem to leap from metres away. (1999)

A large, upright, padded type with medium sized (15cm) oval blue-green pads.  Has lived outside at Cambridge Botanic Gardens since time began.  Hardy.  (1999)

A cholla opuntia growing to maybe 1m tall.  Extremely pretty with golden yellow spines and densely branching habit - this is called the 'Teddybear Cactus' - I, for one, wouldn't want to cuddle it at bedtime.  Could be hardy-ish ? (1999)

A large and impressive cholla that can make a 3m branched shrub.  The stems are smooth and the joints inconspicuous - reminiscent of a green novelty balloon toy.  Apart from the spines.  Unfortunately it doesn't seem that hardy - mine here has been badly damaged by -5C. (1999) 

Low growing padded type with round flat pads 8-10cm across, large yellow flowers followed, I am told, sweet edible fruits.  Hardy. (1999)

A very small, low growing species with egg sized rounded pads, this is extremely variable, flowers feely and probably the most cold tolerant of the bunch.  Not a large imposing plant, but will fill a corner quietly until flowering time.

A sprawling, messy growing padded type, this is almost indestructible.  Variable - some forms are called O. compressa which has lead to all manner of confusion.  Good points: this is often the first choice for people that have never grown cacti outside as it is much more forgiving than most.  It's flowers - nice satiny yellow jobs - are freely produced.  Bad points: it must be said that it is a coarse rampaging thug.  Also in winter it looks like it has been run over by a lorry as the whole plant flops down onto the ground.  This is something that some opuntias will do as a means of getting through the winter and is perfectly normal but it isn't very attractive.  Totally hardy (1999)

A small ground hugging padded type with a lovely purple flushed circular pads and large yellow flowers.  Hardy. (1999)

The hardiest of the tall chollas ( or tallest of the hardy ones ? )  this forms an untidy, upright branched and spiny shrub.  Flowers are reluctant to appear - eventually they are magenta, with a rare white form being particularly nice.  This is another cold weather dangler........Hardy. (1999)

A scruffy tangled cholla with very thin spitefully spined stems that branch profusely.  A bit like living barbed wire.  Hardy-ish (1999) 

This is the Cow Tongue cactus which has very large, elongated oblong pads up to 45cm long, it sprawls around and forms quite large colonies.  It has proved to be one of the hardier opuntias to both cold and wet.  Strictly speaking the name linguiformis can  be given to any species that mutates into this stable 'cow tongue' form - plants in cultivation are more correctly said to be Opuntia lindheimeri forma linguiformis, but everyone knows what we mean.  Hardy here for a couple of years (1997)

This is a strange beast, sort of midway between the padded and chollas in appearance with distinct joints that are rounded and oval in shape, it forms an upright shrub with very brittle joints and very few spines.  Flowers, when they appear, are supposed to be blood red but mine were bright orange.  It seems fairly hardy as well.  (1999)

So far I have found this to be the most pleasing of the padded opuntias to grow.  It forms a large shrub of large grey-green, sparsely-spined oval pads up to 40cm long and keeps upright and steady throughout winter.  It just looks like an opuntia should look and has great presence in the cactus patch.  Flower colour is variable - as indeed the whole plant is with many named cultivars and varieties in cultivation.  Some are larger than others, some have red flowers, some have orange flowers , some have yellow flowers with an orange middle..... and so it goes on.  Lovely.  Hardy. (1999)

A very large, padded species with enormous lorry-wheel sized pads that are almost completely circular, very few spines and a lovely blue-grey colour.  Stays upright and, in Mediterranean areas at least, makes a head high shrub or taller.  Hardiness - maybe ? (1999)

Medium sized padded type with an upright habit, pale olive green pads and densely spined.  Maybe hardy ?  Doesn't like wet too much, but then neither do I.  (1999)

Chunky sprawler with up to 30cm circular dark green pads which flush purple in drought.  Large, bright yellow flowers often have a red throat and the fruit is said to be sweet tasting.  Hardy and said to like water - but the person who said this lives in a desert.  (1999)

Smallish cholla, very spiny, cold hardy, might be ok.  (1999)

Strange one this - little green sausage-shaped joints with very few - if any - spines at all.  Deep red flowers.  Hardy.  (1999)

Another cholla, very congested spiny shrub.  Very hardy.

OREOCEREUS

Hairy columnar cacti from high altitude deserts of South America.  They get very cold in winter when dry, and get quite wet in summer when it rains.  What happens when the get wet and it is cold remains to be seen.

The larger species and quite variable - typically quite sparse white hair, reminiscent of a mad scientist on small plants, with lovely golden spines protruding through the hair.  Relatively fast growing, making columns maybe 2.5m high ( some populations stay below 2m, one reaches 4m ) in the wild and branching from the base to form upright colonies.  Interesting prospect....(1999) 

Smaller species, should be hardier to cold as it is from higher altitudes, and more often than not the columns fall over and grow sideways.  Just as interesting. (1999)

TRICHOCEREUS

Most of these have been lumped together with echinopsis, but I have chosen to ignore this as it seems convenient to keep together these hardier prospects which for some reason seem to fall together within trichocereus.  Anyway from various parts of South America some of these are the nearest thing we are ever likely to get to a Saguaro growing in this country.  Definitely worth trying in dry conditions anywhere in  the country but especially Central London and the drier eastern coasts.  

Formerly in the genus soehrensia, sometimes seen as lobivia, often encountered in echinopsis, this is eventually a small columnar cactus reaching maybe 20cm across and 50cm high.  red flowers.  Sometimes classified as E. formosa, though some people say they are separate.  Hardy. (1999)

Similar to the above, globular cacti eventually forming a small column.  Attractive yellow spines.  Should be hardy.  (1999)

A tall, fast growing columnar cactus that is fearsomely armed with straw-yellow spines.  May be worth a try.  (1999)

Another of the smaller globular types.  Should be hardy.  (1999)

Often referred to as the Argentinian Saguaro, this is a tall columnar cactus with well defined ribs and less conspicuous darker spines.  Could be hardy (1999)

Globular cactus, similar to preceding ones.  Should be hardy (1999)

Extremely attractive tall columnar cactus very densely covered with long golden spines.  Lovely and may be hardy.  Some forms of this are sometimes encountered under the name Helianthocereus poco.  May be hardy (1999)

One of the thickest and tallest, this makes a huge telegraph pole of a cactus.  It may be hardy. (1999)

 

< bromeliads-index-cannas >