Let's grow some Melocactus!

Discuss repotting, soil, lighting, fertilizing, watering, etc. in this category.
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jp29
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Let's grow some Melocactus!

Post by jp29 »

I grew a great many Melocactus a number of years ago and had a collection consisting of mature plants of just about every species available at that time that I grew from seed -- or that Dan Bach gave me. Here is a pic of part of that collection (with a couple of Discocactus thrown in):

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Caveat: I dug that pic out of an archived folder on my PC. The quality (resolution) isn't very good because it was taken before the advent of widely available digital cameras. That holds true for many of the Melocactus pics I will be posting to this thread.

I think Melocactus have a tarnished reputation (a "bad rap") with most cactus enthusiasts (especially beginners) as being very touchy and difficult to grow. Well they certainly have different needs and require a somewhat different growing environment than most other cacti, but they are very rewarding plants if those needs are met. These are warmth loving cacti - they only grow naturally in tropical regions, in many cases in close proximity to the ocean. In cultivation they mostly do not tolerate well cold greenhouses or cold drafty windowsills - they mostly prefer a bottom winter temperature no lower than about 40 degrees F.

Seedling and small Melocactus grow very well as indoor windowsill plants where they flourish in the winter warmth. They do not need any winter rest. Small growing species such as Melocactus matanzanus can be grown to maturity on windowsills (and staged outside during warm weather) where they make striking specimens with their bizarre and colorful cephaliums that produce rossettes of pretty flowers followed by crops of pink, red or white fruit.

I think Melocactus have kind of been cloaked in mystery and shrouded in myths for many cactus enthusiasts for a long time. I would like to give you all my take on some of those myths:

1. "Cultivating Melocactus is very difficult and should only be undertaken by skilled and experienced growers" Not true. If their needs are met they can be easily grown and maintained by beginning growers.

2. "Melocactus have very widespread and shallow root systems and should only be cultivated in wide and shallow containers". Not true. Healthy, robust and perfecty formed plants can be grown and maintained in regular containers as can be seen in the pics accompanying this thread.

3. "They must be grown in porous clay pots to insure proper root aeration". Not true. They grow very well in plastic or glazed pots. In fact, porous clay pots are a detriment -- the watering solution evaporates through the porous sides robbing the plant of nutrients and eventually leads to unsightly containers.

4. "They are very difficult to re-pot and their root systems should not be disturbed". Not true. How do you think all of the large, mature, specimens I depict in this thread ended up in those big containers? Do you think I planted them there when they were little seedlings? Obviously not. They were all "up-potted" as they grew -- many of them several times even after developing cephaliums, All that is required is that the re-potting be carried out in warm weather (I prefer early summer) and that they be placed in a warm location after re-potting.

Root system of Melocactus zehntneri:

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BTW, I personally break up the root ball gently and slightly on my own plants, trimming off any straggly or broken roots. I then let the roots dry off well and then pot the plants in my barely moist (and fresh) growing medium in order to better and quicker re-establish them . I do not wash off or treat the root system prior to potting. I have never lost a Melocactus using this methodology. Having said that, you should wash and treat the root system of plants you buy or receive from others or if you suspect any root mealy bug infestation etc. before re-potting.

EDIT: Revised Cultivational Information:
Much of my cultivational methodology is based on that espoused by Dr. Franz Buxbaum in his book CACTUS CULTURE BASED ON BIOLOGY (translated by Vera Higgins), Blandford Press, 1958. He was the father of using coarse inorganic growing media for superior root aeration; acidifying water & soil by testing and modifying the pH; and using non-porous pots.

I use a General Hydroponics GH1514 Ph Control Kit to test and modify pH.

CONTAINERS: I mostly use plastic pots with generous drainage holes.

SOILLESS GROWING MEDIA: I have always used very open and porous media in order to insure superior drainage and root aeration.

I presently use an inorganic medium that consists of just one component -- what I call "freshly mined and raw" pumice - unscreened with all the fines present - it tests at neutral pH 7.4.

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Raw, unscreened and unsifted/unwashed, pumice as described above

I don't screen out the very small granular pumice fines - but I do wash out the dust using a fine sieve in conjunction with a "power spray head" garden hose as dust tends to migrate to the bottom of containers where it can form a drainage impeding "sludge".

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Washing out dust using a "power spray head" garden hose and fine sieve
Washing continues until the water from the sieve is reasonably clear

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The pumice described above after washing it to remove dust
I perform a final rinse wash using my acidified city tap water.

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Discocactus grown in pumice prpared as described above

I do not use any gravel or crushed rock top dressings for my containers as I have found that they impede the natural surface evaporation I desire.

...............................................
A mix that I have frequently used with excellent results consists of 80% pumice prepared as described above and 20% aged and weathered pine bark screened to remove large particles.

Unlike the Inorganic growing medium described above, these two mixes contain organic components that will require different fertilizing regimens from that described below.

You could just as well use an open and porous "gritty organic mix" (maybe with fired calcined clay such as Turface or a similar product) that provides good aeration and drains well.
..............................................

WATERING: I insure my plants receive copious amounts of water during the hot Arizona summer months. When I water during this time I do it from above and soak the plants until water runs freely from the drainage holes. I use a watering can with Tucson City tap water which is somewhat alkaline (variable pH 8.0 to 8.2 according to the City Water Department). Habitat information suggests that these cacti grow in a somewhat acidic environment and so I adjust the city tap water so that my growing media/water/nutrient solution mix tests at pH 5.5 to 6.0. During our Arizona summer "Monsoon" thunderstorm season normal rainfall (quite acidic in the pH 5.0 to 5.5 range) satisfies the needs of my container grown plants. I use my "adjusted city water mix" for any augmentation watering.

During very hot weather here in Tucson -- 100°F+ days with 75°F+ nights, which equates to roughly late May until mid September -- I sometimes have to water my small container grown cacti just about every other day (except, of course. for "monsoon" thunderstorm days). Actually, because these cacti are CAM plants (stomata opening at night during very hot weather) I water at early evening during this time.

FERTILIZING: In general I feed my plants with each watering during the growing season (spring through autumn) using liquid NPK 5-7-5 fertilizer (containing Magnesium and Micro-Nutrients) in conjunction with my pH adjusted city water.

SUMMARY: I am actually growing these cacti "semi-hydroponically" in that I don't re-cycle or re-use my watering solution

While the approaches, techniques and methodologies I outline above have worked well for me, they may not work well for others who I am sure will find ways of cultivating these plants better suited to their own growing environment and methodologies.

Edit -See my signature block for my updated cultivation methodology

There will be many captioned Melocactus photos to follow.
Last edited by jp29 on Fri Aug 22, 2014 11:43 pm, edited 31 times in total.
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Re: Let's grow some Melocactus!

Post by jp29 »

No doubt about it, Melocactus matanzanus is the most widely available - and grown by enthusiasts - species. This miniature Cuban plant has many desirable attributes: it has a beautiful symmetrical apple green body, prominent ribs with nicely curved and neat spines, it develops a striking orange bristly cephalium at maturity and can be maintained in very small plastic pots.

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Last edited by jp29 on Sun Aug 03, 2014 1:32 am, edited 2 times in total.
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Re: Let's grow some Melocactus!

Post by jp29 »

To me the real gem of the genus is Melocactus azureus. Following are some pics of mature plants.

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Last edited by jp29 on Wed Aug 13, 2014 4:39 pm, edited 1 time in total.
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Re: Let's grow some Melocactus!

Post by jp29 »

I also think the following form of Melocactus ruestii (syn: M. curvispinus) is spectacular with it's symmetrical body, neat spination, prominent pure white wooly cephalium (which contrasts beautifully with the magenta flowers) and large ivory colored juicy fruit:

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Re: Let's grow some Melocactus!

Post by jp29 »

In my front garden this afternoon - a mature Melocactus salvadorensis that I grew from seed about twenty years ago. It has been up-potted several times from a 2" square plastic pot to the present 10" round plastic pot.

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Pilif
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Re: Let's grow some Melocactus!

Post by Pilif »

A very interesting topic!

I'm currently growing quite some melocactus species from seed (ranging from 1-5yrs), but I'm noticing they're very susceptible to spider mites. Was this your experience as well? I'm not quite sure what might be the cause...
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Re: Let's grow some Melocactus!

Post by jp29 »

Pilif wrote:A very interesting topic!

I'm currently growing quite some melocactus species from seed (ranging from 1-5yrs), but I'm noticing they're very susceptible to spider mites. Was this your experience as well? I'm not quite sure what might be the cause...
I have not had that experience for many years now.

Here are two good reference resources:

http://www.gardeningknowhow.com/plant-p ... -mites.htm" onclick="window.open(this.href);return false;

http://www.wikihow.com/Get-Rid-of-Red-S ... rganically" onclick="window.open(this.href);return false;
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Re: Let's grow some Melocactus!

Post by jp29 »

Melocactus andinus is unusual in that it's main habitats are in the Andes mountains of Columbia and Venezuela (hence the specific name). It is reported to have been found at altitudes of 2000+ meters. Because of that, some growers claim plants of this species are somewhat cold hardy (compared to other Melocactus). My experience has been that several mature plants of this species that I grew from seed survived winter temperatures down to 35 degrees F in one of Dan Bach's unheated greenhouses unmarked and otherwise unharmed. But several other mature Melocactus of diverse species also survived those temperatures in that greenhouse unscathed.

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Re: Let's grow some Melocactus!

Post by jp29 »

One of the most common Melocactus found in the state of Bahia, Brazil is M. ernestii - a great favorite with hobbyist growers because of it's long, often contorted, spines and bright red fruit:

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Re: Let's grow some Melocactus!

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Melocactus Violaceus (syn. M. melocactioides) (unresolved: M. margaritaceus)

This is a small growing species that attains about the same dimensions as Melocactus matanzanus. To my my mind this is one of the most beautiful Melocactus with it's dark green body, neat cephalium and pink fruit. For many years it was offered in the trade, and grown by hobbyists, as Melocactus melocactioides. Plants bearing white fruit are considered a distinct species (Melocactus margaritaceus) by some and as a varietal form by others.

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Re: Let's grow some Melocactus!

Post by jp29 »

Melocactus broadwayi is a Carribean (mostly, West Indies?) species that I don't think is grown very much by hobbyists these days.

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Re: Let's grow some Melocactus!

Post by Brunãozinho »

Quite interesting James, thanks for all the info and pictures!
Do you know the origin (locality) of the M. violaceus and M. ernestii seeds from wich you grew these plants?
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Re: Let's grow some Melocactus!

Post by oldcat61 »

James - I have several melos with no ID. Do you feel it's important to know the exact variety or is the care the same? They don't have cephs yet, so I know it's hard to be sure. Thanks, I'm really enjoying this thread. Sue
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Re: Let's grow some Melocactus!

Post by jp29 »

Brunãozinho wrote:Quite interesting James, thanks for all the info and pictures!
Do you know the origin (locality) of the M. violaceus and M. ernestii seeds from wich you grew these plants?
Thanks, Bruno. I no longer have all of my Melocactus notes but I think those were Hildegard Nase seeds that I got from Dan Bach.
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Re: Let's grow some Melocactus!

Post by DaveW »

You pay to heat my greenhouse in winter James and I will grow Melocacti and Discocacti! :lol:

I had not heard of Hildegard Nase as a seed supplier, so did a web search but only came up with this from a 1978 publication.
NASE.png
NASE.png (281.04 KiB) Viewed 43076 times
Evidently she was wholesale only and may no longer be in business?

Unless she collected in habitat Bruno she must have got the originals from some other collector herself.

You can find localities by using Ralph Martin's field number finder Bruno. This finder allows you to type in plant name and lists all localities for it on the database:-

http://ralph.cs.cf.ac.uk/Cacti/finder.html" onclick="window.open(this.href);return false;

http://ralph.cs.cf.ac.uk/Cacti/finder.p ... +violaceus" onclick="window.open(this.href);return false;

http://ralph.cs.cf.ac.uk/Cacti/finder.p ... s+ernestii" onclick="window.open(this.href);return false;
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