Weeds

How do I get rid of a huge infestation of invasive Bishop’s Weed?  It is into and under everything!   I do not want to use Roundup.

The qualities that make a plant a good ground cover also make them terrible weeds. A ground cover needs to be resilient, able to spread quickly to fill a space and recover from any damage. They need to be relentless—like Roman legions—tightly grouped together and marching forward to take over new lands with a constant supply of fresh troops. Bishop’s weed—also known as box elder (Aegopodium podagraria)—is a similar invader. At first, it tempts us with its civilized ways—so attractive, so tidy, so bright. It seemed to be on our side, crowding out other weeds while supporting our garden culture.

Soon enough, though, its aggressive nature turned on us. It started crowding out other plants and dominating every bed it was in. It spread through fleshy underground roots (rhizomes) that could withstand a lot of damage and quickly bounce back. Worst of all, it sent out saboteurs through its seeds. These little spies would pop up in unsuspecting places—everywhere from other gardens to neglected areas, and, worst of all, our woods. It also lost its veneer of civility as new generations of seedlings stopped being variegated. Now, we have to live with the terror of its subsequent generations.

It's tough to root out. The roots are resilient, and they break easily, making it very difficult to eliminate. The seeds will always be there. I’m afraid the only way to deal with them is a constant battle.

1. Keep digging - you may not win the battle, but constant attrition will weaken it.

2. If you cannot dig it out, cut back the foliage - this doesn’t help much but it will reduce its food source and it will help eliminate the flowers 

3. Don’t let it set seed!

Fewer seeds and reduced vigor won’t eliminate it, but it will make it a less formidable enemy. 

Keep fighting the good fight!

Dividing Yucca

I have an Adam’s Needle Yucca which has two flower stalks. I would like to divide it but have no idea how or when to do this. What do you advise? Mary B

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Answer:

Yucca divide well but you have to dig deep. Sometimes the root junction is pretty close to the surface so you can try to separate the offshoot by digging around it to find where it connects to the main root. When you find the junction use a folding pruning saw to cut it off. The parent plant likely won't even notice the separation. 

I would wait until early spring (March) and use the folding saw to cut off ALL the foliage (don't worry, it will grow back.)

If you'd want to dig up the entire plant, use a narrow spade to dig around it, going at least a foot deep. The root system will resemble a horseradish that you can divide so each new plant has some root. The parent is immortal: the  roots are very deep and tough, and it is almost impossible to dig it all up by hand. 

If you only want to remove some extra flower stems, just cut them off when you see them (usually around May). 

While I’ve never dug up a whole yucca myself, I would imagine its root system can be as big as your arm!

In this image, the quarter is at the root junction and you can cut off the two offshoots. It’s easier to see if you dig the whole thing up, but you can feel around in the soil - they aren’t that hard to find with your fingers.

The roots can get much thicker than this , Source: Arkansas Native Plant Society