Ensete ventricosum comes from the Ethiopian highlands, the country which was once known as Abyssinia, conditions considerably more mild than the zn 8a or 8b I experience here in inner SE Portland, so here’s what I do:
Fall weather here can be very volatile. The stable, dry, monotonous even days of summer are shifting and the swings can occur quickly, so I suggest that you pay attention. In general, I like to limit the time my plants spend in storage so I will often leave these in the ground up until the night before a predicted hard freeze when the temperature is expected to drop into the mid to upper 20’s F. Repeated and scattered low temps into the upper 20’s can accumulate and do damage, so keep this in mind. Storage doesn’t improve a plant’s health. In fact, once dug and stored it is a period of decline until once again they can be replanted outside and put on new growth. Many of my containerized plants shuffle back and forth, spending only periods of sustained freezing weather in the ‘warmest’ storage place, the basement. Plants acclimate slowly so putting them in and out only works if they are protected for relatively brief periods…too long in a ‘warmer’ place and their metabolism is awakened, their ‘hardiness’ reduced, thus increasing the likelihood that their return to outside will be damaging. With plants like the Ensete, the tropicals I grow, once I bring them in, they stay in until I determine to put them out.
‘Normally’ I don’t bring the Ensete in until after Thanksgiving. It will take a frost and a light freeze without significant damage. It will not turn to black mash like Coleus with the first minor freeze. Its cell structure is more robust…but not a lot more. Often these events can be very scattered so I leave it out where it can better maintain the turgidity of its tissues. Another consideration in the fall is wind. Wind can do serious damage to a standing Ensete.
An Ensete‘s leaves are huge paddles and if the wind is very strong at all, it can shred them, splitting them along the veins to the stouter mid-rib. These should be sited out of the wind to preserve the leaves intact during the growing season, otherwise one of its most desirable traits is lost. (This shredding damage is aesthetic and because it does not tear across the veins, does not impair a leaf’s ability to continue photosynthesis or to metabolize.) In the Fall wind tends to increase here and these winds can more than shred your leaves. All Bananas are monocots and possess no wood tissue. Their main stems are not woody. They have no trunk or strongly attached branches. Their trunk is in fact a ‘pseudo-stem’, from here on the ‘p-stem’, a tightly packed bundle of modified leaf tissue. Each leaf from its apex at its drip tip down to its beginning at the plant’s base is a continuous piece. All of the ‘top growth’, each leaf, originates from this single basal structure. This is its meristem. There is no apical meristem in its ‘crown’. All growth initiates from this single all important point. There is not cambium adding girth and rings. Each continuous leaf ‘wraps and clings’ tightly to the others, the newest pushing up through the center. So, when the wind blows hard enough the leaf blades exert enough torque to the pseudo-stem to separate these from this bundled structure. When this happens they lose most of their integrity, fold at some weak point and fall to the ground, breaking, crushing, some of the cell structure that once supported the ‘leaf’. Do this enough and the whole p-stem can break apart. This is important because this structure stores the moisture and energy that will get the Banana through the induced dormancy of winter storage.
Other bananas, true bananas, genus Musa, are also monocots and grow much the same way with one exception, they produce a rhizome that spreads and increases in a large bulky mat forming clonal colonies with. Ensete, at least those grown in temperate climates where these cannot mature and flower, have a much smaller rhizome that basically is limited to the width of the pseudo-stem. In both cases the rhizome stores starches so that even if they lose all of their p-stems they will come back with vigor. The p-stem does contain water that the stored plant can use to maintain itself.
A gardener who grows Ensete has a choice, 1, Move the plant into storage before a freeze or wind
can do any significant damage, or 2, reduce the sail effect by removing the older leaf blades which are held at a low angle and are thus more likely to be ‘torn’ free by the wind, and/ or, reinforce the pseudo-stem tying it with a piece of fabric just below the point where the leaves begin to flare out. Don’t use a string or rope as it can cut into or crush tissue. Some wind conditions can lead to toppling of the whole plant if the ‘sail’ is not reduced. If the winds kick up while temps remain moderate, I will follow 2.
At some point you will need to dig your plant. These can be deceptively heavy and most of the weight comes from the water that they contain. The physical material that make up the top growth of an Ensete is pretty insignificant though the rhizome itself can be quite heavy. Its stem and mid-rib structures are akin to Celery with large open cells and fibers tying them together. Cut one and water flows out. I cut the whole plant off just below where the leaf blades begin. It takes one swing of a machete. There is little resistance.
These are simple to dig. There is no broadly spreading root structure to protect as there is with ‘woody’ plants. There appears to be very little root structure given the size of the top growth. All of the roots originate from the aforementioned bud of meristematic tissue at the plant’s base.
The roots don’t branch. The structure looks something like an old fashioned mop with thick, white, fleshy roots. I am still amazed by this plant’s vigor when I look at its roots. The plant won’t be growing when it’s stored as in the cool dark, so there is no need to keep the soil around the roots. It just adds weight. I don’t pot it either.
Once free I lay it on a blue tarp, wrap it up as if it were a diaper and tie it in place. It is usually too heavy to carry through my garden, down the 7 stairs, around to the front and then into the basement, I’m guessing 200lbs+. I get it on a dolly, roll it to the stairs, skid it down a plank, get it back on the dolly and wheel it around through my street grade basement door, get it close and then stand it up where it will spend the winter. I stand it, because it never really stops growing.
Ensete don’t have a freeze response. If its cold enough they just die, first the essential meristem. But, they do have a drought response. This storage technique is taking advantage of its drought response. A cool room will slow the metabolism rate down to the point where it won’t exhaust its reserves before it gets through the winter. When under drought stess an Ensete, unable to draw moisture from the surrounding soil, none in this case, will draw moisture and nutrients, from its outer most leaves back down to the bud to keep growing. Over time, in storage, the outer most growth will dry like raisins until its crisp while new leaves continue to slowly form and extend. 40º-45º is probably ideal. (Mine is too warm! Oh well!!) This will slow metabolism. There is no need to light the space and low light will encourage the formation of fragile, thin walled, etiolated, cells that will be shed when the plant is returned to the garden. You want to minimize the time in storage as this will lead to more tissue being metabolized and weakening the plant. Now you can see why damage done to the top growth before you bring it into storage will reduce the ‘reserves’ the plant has to use and result in a smaller weaker plant in the spring when it is planted out. A lot of people cut their bananas off low, just above the rhizome and meristem. I prefer to leave more of the p-stem in place for the reasons above.
When the weather has warmed and stabilized enough, after your last freezing lows, when highs are consistently above the mid 50’s and are supportive of active growth, you can bring it out. I cut the weak, etiolated, blanched growth off that has appeared over the winter. The plant will still be heavy. I’ve never weighed it going in or coming out, but I wouldn’t be surprised if it lost half of its water weight. Prepare the hole. I usually add and work in compost. Part of the process is to loosen the soil so the Ensete can ‘settle’ in to its spot. Don’t bother trying to fan out the roots or ‘build’ a center cone to stand the plant on. Whatever you do will be crushed by the weight of the plant. Don’t bury the crown or bud in an attempt ‘brace’ it. Set upright on ‘loose’ soil without any leaf blades to catch wind, the plant will tend to stay solidly in place. It will shed its old damaged roots and initiate new ones soon enough, re-anchoring the plant. I’ve never had one topple in a spring wind before. Over time cut away the dried husks of the old leaves, but be careful not to cut into of the healthy growth as that could compromise it. Fertilize and water as needed and you’re good to go for another cycle.