So I recall a while back someone somewhere made a comment that there was not a lot of information on these guys and that that was the reason no one grew them or took up offers for them.
I was drafting up something for a friend and decided to go whole hog so here you go.
And please remember that this is just my guide for what works for me. It is meant to give pointers and I will not under any circumstances swear that my techniques will work for everyone else.
How to Grow Utricularia (a.k.a. Orchid flower Utrics and Epiphytic Utrics)
* Note: While these species are often clumped in with the Iperua section they are distinctly different and have different cultivation requirements. This group includes U. alpina, asplundii, jamesoniana, endresii, praetermissa, quelchii, campbelliana, unifolia, and buntingiana. I currently grow all but the last three.
In my years of growing these plants my choice of media has evolved. Here I will detail that evolution and discuss the pros and cons of each stop along the way. I will also note that the only species I grew at the time I tried the early medias was U. alpina which is the most forgiving of the species. *My initial media for this group was the one detail in The Savage Garden. I found that this media compacted quickly and would develop the sulfur stench indicative of anaerobic bacterial growth. The compaction was the main problem as compact media does not drain and these plants are very picky about being too wet for too long. I have nothing good to say about this mix.
My next media was my standard Nep media, basically a mix of orchid bark, LFS and horticultural charcoal. This mix drained more freely than the previous mix but I still found that it would compact over time to the detriment of the plant. Around this time I acquired U. asplundii, My attempt to grow this plant in the above media resulted in my almost losing the plant and prompted my next media change.
Note: If grown in hanging baskets supplied by overhead watering or heavy misting any of the below media should work.
My third media was a mix of 2 parts LSF to one part fine orchid bark. Both U. alpina and U. asplundii grew well in this mix, which drained freely and never developed anaerobic conditions. However, in time the LFS would degrade and compact leaving nothing but the orchid bark, which was not as amicable to further growth. During this time I acquired U. praetermissa, U. endresii, U. ‘Jitka’ and U. quelchii. These plants were given to me by a grower who used a 2:1 perlite:LFS mix and under his suggestion I again switched media.
The perlite:LFS media worked well for a long period. The media drains well while holding a good suppl of water. However, given my watering/growing technique I came to the conclusion that this method still resulted in too much moisture, compaction of the LFS and formation of anaerobic conditions.
Around this time I came across a couple references to Cyprus mulch and its anti-microbial properties. While I was hesitant to try a totally unknown factor in my media I had previous experience with pine bark mulch (the brand I use is sold under the name Nature’s Helper soil conditioner but I believe any brand should work fine.) I would wash this pine bark mulch until all the fines had been rinsed away and then use the remaining bark pieces to fill half of the pot. I would then fill the remainder of the pot with an equal parts mix of perlite, pine bark chips and LFS and I would top that with a few sprigs of live sphag. This combination proved very successful for most of the species, the exceptions being U. endresii and, I learned later, U. quelchii. All the plants (except U endresii) grew strongly in these media and I was able to divide each annually.
It was during my last annual division process that I noticed something that led me to my current (and hopefully final) media/growing technique. What I noticed was that despite long periods of growth in the pots the only plant that put stolons down deeper than the first few centimeters was U. alpina. All the other species had filled the top few centimeters with stolon material which in some cases was “escaping” over the sides. I also noticed that the stolons were most dense in the patched of live sphag.
I had often heard of other growers using LF NZ or Chilean sphag and this was the most quoted media when I was first looking into growing these species. I had not had success with this choice of media (the first U. alpina I grew I placed in this and lost it before it even recovered from shipping shock) so I had written it off from the very beginning. The dense growth around the live sphag made me rethink this idea.
Obviously live sphag is now my current media. I grow my plants in a rather complicated “Slack-potting” style (I have attached pics showing the details) but I am sure that a pot filled half way with something well draining (perlite, pumice, coarse orchid bark) and topped with live sphag would work just fine. The only plant I do not grow in live sphag is U. jamesoniana, which I grow in either pine bark mulch or peat:sand both in my “Slack-potting” style and also in standard pots. From reports I also suspect that U. campbelliana might grow well in these same media
These plant must be grown in drained pots as they require excellent drainage. Orchid baskets and water lily-style net pots are an excellent choice as they provide extra air circulation through the media but standard style pots work fine as well. In time these plants will grow to fill most any pot so any size will work, most species do fine in 7-10cm pots but larger pots do not hurt. I have found that lateral spread is more important than depth for these plants so half height pots are another possibility. There has been some discussion that these plant need to reach a critical minimum size before they flower, 15cm pots being the most often cited minimum to attain that size. I have never found this to be ture having had plants bloom when in pots of 7cm
These plants are best treated along the lines of Nepenthes, i.e. watering to keep the media damp but not soaking wet. However, that being said these plants have no set watering requirement and often what works well for one may not apply to others. I find that U. alpina is the most tolerant of excess moisture often growing well under conditions that would cause the loss of other plants from this section. My current “Slack-potting” method entails putting a half height net basket in a standard pot and threading some strands of sphag *out the bottom of the basket to hang to the bottom of the regular pot. I then place the whole set up on the tray system with water 1-2cm deep and top water whenever the tray dries. Plants grown in hanging baskets can simply be top watered often enought to keep the sphag happy and growing. If using any of the other potting methods/medias the method I found to work well was to use Styrofoam blocks under the pots in trays and top-water when the LFS starts to get a little dry. By setting the pot on the block the excess water drains away but its presence in the tray creates a higher local humidity.
Occasionally I will observe stolons growing out the bottom of the pot and into the tray. While this might seem to contradict my statement that these plants prefers drier conditions I would also like to note that these sections of stolon never develop leaves and tend to not “travel” much more than a few centimeters from the point where they exited the pot. During periods of dormancy or slowed growth the media should be kept somewhat drier to avoid rotting of the stolons/tubers.
Previously I have grown all of these species under 4 120cm fluorescent tubes. To provide a broad spectrum I use 2 Sunshine bulbs and 2 warm white bulbs. The lights are hung so that they are 30-45cm above the pots. When grown outdoors I place the pots in areas that get dappled sunlight through out the day, I do not allow the plants to receive full direct sun.
I have recently switched to a 400W MH/HID system on a track. The plants are about 65cm below the light.
While these species all grow in South and Central America the majority are native to highland conditions and grow best under intermediate/highland tropical conditions. In my collection they do best when grown under the cooler conditions of my crawlspace. Day temperatures tend to be between 18-23C, night temps can drop down to 15 during the summer months. Winter temps are about 5 degrees lower. I have successfully adapted a clone of U. alpina to outdoor temps here in Atlanta during the summer so it is possible to grow some of these plants under warmer conditions. Discussions with other growers has led me to believe that these plants may be able to handle temps up to ~30C but only for very short periods and humidity must be very high. Extended periods at these temps often lead to the plant dying, though some (such as U. endresii) may come back from their tubers once temperatures drop to a reasonable level.
There are also some species that have ranges down to sea-level. If you have a clone that is known to be from such a locale it might survive well under higher temperature conditions.
Growing the plants as I described above allows water to drain from the pots into the tray creating an increased local humidity in the range of 50-90%, most often about 70%. I assume these plants can be conditioned to somewhat lower humidity levels but this should be done slowly as the leaves are very thin and would likely dry out rapidly.
The epiphytic Utrics have a variety of dormancy/pseudo-dormancy patterns. Most of the species commonly in cultivation (i.e. U. asplundii, U alpina, U quelchii) exhibit a seasonal slowing or cessation of growth. During this time the media should be kept only damp and it is better to error on the side of too dry than too wet. U. endresii is reported to have a true dormancy period where its leaves will die back and the plant should be kept on the dry side. Humidity should still be high enough to prevent desiccation of the tubers.
These plants are propagated most easily via division. A clump is best taken from the mother plant during active growth and potted up it up in new media, ensure you keep the humidity high and the media only moist (if the media is too wet the plants tend to rot) for the division and the parent plant. This procedure may result in the division (and in some cases the parent) losing many or all of its leaves. Continue to treat the pot as if the plant were actively growing because in many cases the plant is simply establishing itself from the stolons up.
Seed can also be used but it must be very fresh or it will likely not be viable. Sow on milled sphag or a peat:sand mix and keep moist in high humidity. I find the best method to employ is to sow the seed on the media in a small pot and then lightly water and place immediately in a Zip-lock bag. The closed bag retains all the necessary humidity and the small amount of water that drains through the pot and pools in the bottom of the bag acts as a permanent reservoir but does not make for an excessively wet condition.
An easy plant that adapts well to almost any conditions. Can take slightly higher temps, lower humidity and wetter media. The leaves are spade shaped. Flowers are white with a yellow splotch.
Slightly more difficult than U. alpina but grows fast and well once established. It appreciates highland conditions (as opposed to intermediate conditions.) The paddle-shaped leaves are thin and do not react well to rapid drops in humidity. Flowers are white with purple accenting and have a unique triple fork lower lobe. This species has a distinct dormancy period where it ceases all growth. At this time it may even lose all of its leaves but the tubers and stolons remain alive in the media. To keep them from rotting it is best to let the media remain on the dry side until growth resumes.
Only recently introduced to cultivation, this diminutive species is found under a wide range of elevation in nature (sea level to 3000m.) To the best of my knowledge the only clone in common cultivation is from Represa el Penol, Antioquia, Colombia, 1900m and as such it is best treated as an intermediate or highland plant. Cultivation is similar to that of U. asplundii. Somewhat tolerant of prolonged wet periods.
Similar in appearance to U. alpina, the most common clone in cultivation does better under highland conditions though there are some clones from closer to sea-level that may be amicable to lowland conditions. This plant is reported to have dry dormancy period (Belanger, CPN) though other growers note that it will grow year round without showing any noticeable cessation of growth. Flowers are pale mauve.
Another plant similar to U. alpina though the leaves are shaped more like those of U. asplundii. This plant is not common in cultivation but grows well and fast under highland conditions. Flowers are pale pink to white and quite large.
This plant is becoming more common in collections. The leaves are similar to those of U. calycifida. The flowers are bright red. Appreciates somewhat drier conditions and is a definite highland plant.
Rare in cultivation, it looks somewhat like a miniature U. quelchii. Cultivation conditions for this plant are reported to be very difficult to maintain. I suspect (having not actually grown the plant) that it would do well treated along the same lines as U. jamesoniana although I would keep it drier than that species. Flowers are also red though an orange flowered form also exists.
Not widely in cultivation but there are a few growers reported to have it. This plant is very similar to U. praetermissa in form with flowers similar to that of U. endresii. I predict it would grow best treated like U. praetermissa but it is a definite highlander and should be kept cool. Flowers range from pink to mauve.
This has yet to be introduced to cultivation. Like U. jamesoniana this plant is much smaller than the other members of the section. Leaves are tear-drop shaped. Flowers are white with purple.
U. ‘Jitka’ (U. praetermissa x quelchii)
A wonderful hybrid that has the foliage appearance and growth habits of the U. praetermissa parent. It has blooms that are a dark pink with a large yellow throat blotch.
U. alpina x endresii
This hybrid is, to the best of my knowledge, yet to be reliably confirmed. The plant that I grow has the appearance of U. endresii but the growth habit of U. alpina. The blooms very much like those of U. alpina with the exception of the lilac fringe to the lower lip.
U. humboldtii x quelchii
An interesting hybrid that looks like a diminutive U. humboldtii and even retains the trait of puttingout aerial stolons. I grow this plant using the Slack-style method (as opposed to the method I would employ for Iperua type plants) and it appears to grow well this way. The flowers are deep pink and have a shape intermediate between the two parents.
U. alpina x campbelliana
I do not grow this plant but from reports it takes after the U. campbelliana parent and, as such, is more difficult than most of the others in this group. The flower resembles that of U. alpina but is a vivid red-pink.