Age-old ferns are here to stay

Question: Last year I had a few ferns pop up in my perennial flower bed and I carefully surrounded each with cardboard and sprayed it with Roundup. They turned somewhat brown, but never completely died. In late fall I tried digging them all out, but I must have missed some, because this year they are coming up everywhere!

The problem is that they are coming up deep inside the delphinium, lavender, clematis, etc. These plants are all looking so healthy and getting ready to bloom soon, so I don’t want to dig much around them. What can I do to get rid of the ferns, or at least keep them from taking over my garden?

Loretta Evans

Ferns haven’t survived for 370 million years because they were wimps that folded up at the first whiff of Roundup. On the contrary, they thrive in such a wide variety of conditions that they can be found from sea level to 10,000 feet – anywhere there is enough moisture for them to grow. Obviously they have decided your garden is a perfect place.

Ferns consist of a leaf, or frond, held on a stalk that grows from a surface or underground rhizome. They reproduce by dispersing spores in the late summer, through a very complex process. They also spread by means of deep underground rhizomes.

Because they are a primitive plant, their growth cycles and mechanisms are different from plants that we are more familiar with. Controlling them takes persistence as you have discovered. They can be restricted with Roundup and other glyphosate products, but only by repeated application over the year and for several succeeding years. This may be the best thing to do in your perennials where digging is difficult.

Another way to control them is to begin cutting the new fronds as soon as they appear in the spring and keep after them through the season. This will slowly weaken the rhizome system and hopefully starve them out in your lifetime. Digging is the last option, and it only works if you can dig up the entire bed and then thoroughly clean the soil of any roots and rhizomes.

In the meantime, the plants may be sneaking in a little spore production and scattering literally millions of single celled spores all over the place. Fortunately for you, the vast majority of the spores won’t germinate. Cultivate the soil in areas where the ferns are growing to reduce their chances of finding a good growing spot. And on a last note: I actually have friends who said they’d take your ferns. Let me know if you are interested in a relocation program.

Hydrangea turns brown

I have a hydrangea that I’ve grown into a bush from a stick. Every year it is covered with blooms. This year it leafed out early, but then it got cool again and now all the leaves are turning brown and crumbling up when you touch them.

There were only about three blooms and they’re turning brown now. What’s wrong and is there anything I can do to cure it?

Thanks, Beth Schmidt

A couple of things may be going on here.

Your poor hydrangeas may have been caught in the series of practical jokes Mother Nature has been pulling on us this year. First we had no winter, which was good for your hydrangeas. Then, just when the plants thought they could leaf out and get started for the year, nature forgot to turn up the thermostat and their first set of leaves just gave up and died back. There wasn’t much you could do.

The other possibility is that the plant got so dry in February and March this year that it affected the roots’ ability to function, or caused some dieback underground. I was watering rhododendrons in February because they were wilting. If this is the case, you can only hope there are enough roots left to keep the plant going and it will grow some new ones over time.

In either case, it can still send out a new set of leaves, but will probably be set back a bit for the year. Give it a light dressing of 10-10-10 fertilizer, a top dressing of compost and soak it for a couple of hours each week with a slow running hose through the fall. If we get another dry winter, give the plant a little water to provide some moisture when it comes out of dormancy. Good luck.

Arborvitae are dying

The enclosed samples are clippings taken from tall arborvitae that are six feet apart. What is causing the dry-out or death of these nine-foot plants? They were planted 27 years ago. Please give me some information on how to prevent further damage.

Arnold Stueckle, Spokane

The samples you sent were small so it’s hard to pinpoint the problem exactly. I am assuming that this problem has appeared this spring after the dry winter. They probably got too dry over the winter and are dying back now because of that.

Arborvitae are sensitive to dryness and will begin dying quickly once the soil moisture drops to unacceptable levels. Because they are evergreens they transpire through the winter and never go dormant like deciduous trees. Our moisture levels last fall weren’t the best either so if you stopped watering them before the end of October, the plants went into winter too dry to begin with. If these are the only two of several plants in a row that are affected, it simply means that the soil under these two went dry before it did under other plants. This could mean that there is something under ground like a rock or sand pocket that affects how long water stays near the plant roots.

If the plants still show some life, be sure to water them well with a weekly deep soak with a slow running hose. A soaker hose snaked down a line of arborvitae would probably help the whole group in the long run. Sprinklers set to keep a lawn happy are not going to provide the arborvitae with enough water.

If you still have concerns, take some samples of the dead and live foliage to the Spokane County Master Gardener Plant Clinic at the Cooperative Extension Office, 222 N. Havana St. The clinic is open Monday through Thursday, 9 a.m. to 3 p.m., and Fridays 9 a.m. to 1 p.m.