Pot size

[Rob-Rah]

Slightly specious question here, but I'll ask it nonetheless:

What size pot is suitable for epiphytic Utrics? (alpina, humboldtii, endresii, longifolia, nelumbifolia, etc.)

Mine are in 5" square mesh pots but growing out all round the sides - it's good healthy growing I know, but do these plants form huge mats in the wild or are they more or less self-contained at any given size?

Thanks.

[vic brown]

U. reniformis and U. humboltii certainly appreciate much larger pots and most of the others will grow to fill out large ones too. I have seen flowering specimens of most of the other 'epiphytic' utrics you mention in smaller pots though, so really its a matter of your available space. In nature the ones they will spread out to fill all the available free and suitable habitat, forming large colonies if there is room.

Note that U. humboltii spreads out by above ground stolons, so if you have it growing well near your other species, it may well invade them. It 'hops' from bromeliad to bromeliad by this means.

Vic

[Guest tim.]

I have a U. alpina x endresii that has two huge healthy scapes that is growing in a 3in pot. I have also had U. longifolia flower in a 3 in pot.

[Rob-Rah]

I guess the corollary to my question concerns how long one leaves a plant in a pot before having to repot it.

I am planning to put the reniformis, humboldtii and nelumbifolia into 12 inch (or so) waterlilly baskets next year. Endresii seems to be a small-grower for me and is happy in smaller containers, and longifolia and alpina flower in 5 inch pots with no problems.

I have read that Utrics like to be left undisturbed to flower. Is this completely true though? I notice that they all put on substantial growth spurts after repotting. As it's going now, I will be repotting many of the smaller ones once or twice a year!

Any views?

[Giles_KS]

I have read that Utrics like to be left undisturbed to flower. Is this completely true though? I notice that they all put on substantial growth spurts after repotting.

Repotting may just persuade the plants to continue making vegetative growth. Once they have filled their pot and have nowhere else to grow to, they are more likely to put their energy into flowering. If you have the space for a number of pots of each species, you can start a new pot with a small portion of an existing colony whilst leaving the rest of the plant undisturbed to flower, although this is more difficult with the large species due to the stolons going round & round.

Giles

[Rob-Rah]

Repotting may just persuade the plants to continue making vegetative growth. Once they have filled their pot and have nowhere else to grow to, they are more likely to put their energy into flowering.

I can only speak for experience of a handful terrestrials and "epiphytes", but I can see no difference in the flowering habits whether the plant is established, pot-bound, or newly repotted with lots of free space. It's often suggested as the means to get a plant to flower, but I have suspicions that it may be only indirectly realted, if at all. For example, a pot-bound plant will have a greater concentration of bladders per unit volume of soil (for as long as the soil remains effective at transporting beasties - a pot full of stolons and no soil won't do the trick nearly so well), and will be catching more prey and therefore be more likely to flower. But with that in mind, I think that a good condition of soil, plenty of water and light and stable temperatures are far more important in encouraging flowering. Well, for me at least. And it seems from other peoples' reports that the introduction of occasional "feeds" of things like daphnia are more likely to encourage flower production.

[Bob H]

I don't know about Utrics particularly but, flowering is trigerred as a means of genetic survival. If a plant "feels" threatened it is more likely to attempt flowering to spread its genetic material, hence out of season flowering in stressed plants. In situations of high nutrition the plant is more likely to produce vegetative growth, in prep for future flowering.

As I said not sure about the same for Utrics, but makes sense.

[Rob-Rah]

I have heard the same, but I still question whether it is one of those urban-myths....

When, for instance, you grow tomatoes, one type of fertiliser will stimluate vegetative growth, whereas another will stimulate flowering. Nothing to do with stress. What is really happening is that the plant is looking for optimal conditions for its seedlings to grow in.

Stressed plants do produce flowers out-of-season, but I would not make the leap that the means to achieve flowering is to stress the plant - it can only be a bad move. To anthropomorphise for a moment, if I were a plant, I would not want to produce lots of seedlings in an area already full of my own roots, but would rather produce them in an area where they had good soil and plenty of space for themselves.

For sure things like strelitzeas and figs do wayyy better when pot-bound, but I don't see any reason to assume that this is a general rule.

[Giles_KS]

I'm also not sure how this applies to Utrics, and there is probably a difference between species and reproductive strategies - annuals are obviously going to behave differently to perennials.

In a lot of plants, addition of lots of nitrogenous fertiliser will promote vegetative growth and suppress flowering. it makes sense for the plants to grow lots of leaves when they can and they are happy, as these will produce compound returns, i.e. the plant will eventually be able to produce far more flowers & seed by waiting & growing leaves then flowering immediately. Stress flowering occurs when the plant thinks it's going to die anyway, so it puts as much of its energy as possible into flowers & seed.

if I were a plant, I would not want to produce lots of seedlings in an area already full of my own roots, but would rather produce them in an area where they had good soil and plenty of space for themselves.

On the contrary, of there was lots of available space, I would grow my roots into it as quickly as possible before another plant did, then I could produce even more seeds with the extra nutrients. Plants are not growing in a vacuum where they can afford to leave vacant space for their offspring' they must fill it before their neighbour does.

To draw an analogy with economics, rapidly growing companies tend not to pay dividends - they invest their money knowing that this will produce greater future returns. Once they have reached a point where they have nowhere to grow, like a pot bound plant, they have nothing better to do with the profits so pay dividends.

Giles

[Bob H]

The availabilty of the nutrients is the key.

In a root free environment there is a higher percentage of nitrogen, compared to a root infested area. This leads to vegetative growth. In contrast rooty soil will be lower in nitrogen, as this is taken up at a great rate than all else, and higher in the phosphates ect that stimulate growth.

As you say with stressed plants it is a different reason but same effect. When stressed the roots absorb the "healing" nutrients in prference to the growth nutrients, thats why the plants take a while to settle in, survival tactics.

[Rob-Rah]

Ignoring the issue of stress, is there any reason why a plant would make vegetative growth at the expense of flowers? If it's happy, why should it not do both? (as mine seem to do)

[Bob H]

They will, thats their programming. But by limiting the nitrogen available shifts the emphesis towards spreading their genetic material away from the depleted area, ergo seed production (not flower production, not all seed bearers have flowers!!!!). If conditions are optimal, right balance of nutrients and other factors (light, water, humidity, sky sports, adult fantsay channel ;-) ) then the plants follow their program path, and may increase their flowering potential by over production of vegetation, which not only provides the means for further seed making but an increase in food stores to power said same. I think, any way IMHO. :-)

[Giles_KS]

Ignoring the issue of stress, is there any reason why a plant would make vegetative growth at the expense of flowers? If it's happy, why should it not do both? (as mine seem to do)

Nutrients & energy that have been put into flowers/seeds are unavailable for growth - there is bound to be a trade-off between the two. Different species choose a balance to suit their lifestyle - many trees won't flower for years/decades so as to put all their energy into growth.

Giles

[Guest tim.]

I find that some species produce vegetative growth and flowers at the same time. When they run out of room in the pot vegetative growth slows down and so does flowering. Repotting these species will often result in renewed flowering. (ie. U. calycifida, U. sandersonii)

Other species seem to flower based on seasonal cues, such as day length, or day-night temp differences. These are probably the species that those of us who grow them indoors have trouble getting to flower, yet these same species flower profusely for those who grow them in greenhouses. (eg. U. praelonga, U. alpina)

I would assume that there are also species which flower based on seasonal wet/dry cycles, but I have not had much experience getting these to flower, and have not seen much anecdotal evidence via the internet. (eg. U. leptoplectra?, U. biloba?)

Flowering in the wild would need to occur at appropriate times for pollenation (presence of appropriate insects etc.), seed development, seed dispersal, germination etc. Therefore a plant should not produce flowers unless it recieves signs that these requirements will be fulfilled.