Tuesday, May 06, 2014

Plant Profile: Yucca filamentosa - Maintaining and Sustaining

I find most Yucca filamentosas are never properly taken care of. Folks don't realize that hardy yuccas require regular maintenance and a little TLC to get them to last for more than a few years. Otherwise they die out and look tired.

When healthy, even snow won't weigh down older yucca leaves.
Here's how to maintain them:

Yucca filamentosas expand and grow to become clumps. They flower generally after they reach 2 to 3 years in age.

A long spike of white flowers emerges from the centre of each plant in late June and blooms for about 3 weeks. Once the flower stalk begins to go to seed, the flowered plant begins to whither and die back. The trick is to peak beneath the foliage in order to find little plants emerging from the base.  Sometimes, if the 3 year old original plant starts to fade and wilt over, it smothers the young, new growth that will come from the root system. You must cut out the parent plant and allow the younger ones to breathe and emerge properly. Parent plants will not re-bloom.

Yuccas have deep root tubers. They can go down to 24" or more. Tough plant to dig out. Once the parent plant dies back with the old flower stock, the base of the plant begins to rot and can cause other smaller roots to rot with it. As the foliage starts to brown, the plant beneath loses vigor and it will fall on to itself. Making it rather untidy.

Like I did here, cut the whole parent plant out. Be sure it has the flower stalk like this one.

It is easiest to cut out with open pruners, using the blade like a knife and slice it out as close to the ground as possible. They are like potatoes, quite juicy.
Once all the flowered plants have been removed, you will see baby yuccas around the base of the original plants. 

You may think you've massacred the plant but lo'and behold...there on the left of the remaining stalk base, you'll see a little yucca waiting for light and air to allow it to start the whole process again.

Here's a closer view. The remaining tuber stalk will whither and die back whilst the young yucca will bulk up over the next growing year. This little plant won't flower for another 2-3 years, allowing you to enjoy it's evergreen foliage for a long while before it flowers.
In a clump of yuccas, there will be several plants at several growing stages. Once all the flowered plants have been removed, you will open up more room and allow the remaining plants that were suffocating from the flowered plants to spread out. These yuccas may look a bit little beaten up. Here is where the TLC comes in.

Lift up all the blades of yucca and remove any discoloured or brown leaves from the stem.

Pull down on the leaves - quite hard.

Like celery, they snap clear off the stem without causing damage. If you yank on them upward, you can yank the whole stem away from the root. Always pull downwards.

Old, dry, and damaged blades of foliage should be completely removed, not cut out. You'll need to do this in succession. Leaves wrap around the stem as it whorls up to the centre. Remove each this way, and they will come off with ease. Ripping them out of sequence will damage the stem or leave remnants of the leaf base still attached. These will whither and rot, causing some rot to occur at the root level. You want good air circulation to strengthen the stem.

Yuccas will force new growth from the centre, adding newer leaves during the growing season. Within a growing season, they will become deep green again. Much needed light and air then can help newer growth emerge and keep your yuccas looking vibrant and not limp or discoloured.

Winter maintenance:

Tough winters can cause this - half the foliage yellowing and the main core limp.
If you have many clusters of yucca, all healthy and the flowered plant removed, sometimes it's best to tie up the blades of foliage into a pony tail of sorts. This keeps the foliage off the ground and away from moisture and soil. Rip off one long leaf from the base of the plant. Use it as a binding. Gather the blades at the base and use the binding leaf to keep the plant together. This will keep the foliage upright and away from standing water or mushy soil. Come spring, remove the binding and allow the plant to fall into natural habit.

By removing older plants, newer plants will take over and you will be able to enjoy yuccas in your garden for a very LONG time, without them looking like they need to be yanked out.

Two months after my TLC, this is the same clump of yuccas flourishing again:


  1. Thanks a lot for the steps! Did you ever try growing in pots? Should I simply cut the new Yucca plants from the Yucca mother plant and plant them in separate containers? I have the mother plant in the center and 4 small pups around it that seem to be attached to its roots.

    Thanks again!

    1. Can't say I have ever tried to grow these cold climate yucca's in pots, as they require a fair bit of depth for their tap roots. I have however grown the tropical varieties in the way you have described. The mother plant eventually dies with the cold climate (Yucca filamentosa), but by all means you can try. I would cut the mother plant down as far as one can and the babies beneath will fill out to cover any remaining stalk left behind.


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