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Jeff Lowenfels: Why your hollyhocks disappeared -- and answers to other questions

Jeff Lowenfels

Ah, time to clear off the desk and computer of questions that I call “questions others might like to hear answers to.” As the loyal reader knows, I take questions and almost always eventually answer them, but some are more useful to the general readership than others.

Let’s start with “What happened to my hollyhocks? There were there last year, but not this year.”

Not everyone grows hollyhocks. And this question highlights a problem that gets in the way. For starters, hollyhocks are biennials. They last two years and then disappear. How long has your plant been in the ground? In addition, hollyhocks are marginally hardy here in Southcentral. They need great sun and if possible, as much protection from the wind as you can give them. Finally, they need to be mulched in the fall if it is their first winter.

The real trick to hollyhock growing here in Alaska is to start them in February. This is almost always early enough so that they will flower the first year and can be treated as annuals. They are show-stopping plants and everyone should give them a try if they have the room and time.

In the same vein, some readers complained that their dianthus (aka Sweet Williams or “pinks”) didn’t come back this year. This might be because they were annuals and not perennials. Most don’t know that dianthus come in annual, perennial and biennial forms. The perennials don’t do well here and the ones you buy in the nurseries are almost always either annuals or biennials. One or two years and they are gone. There is one reason why I harp on keeping labels for plants.

Next, a reader lost all of her Lewisia this winter and wants to know why. This is a wonderful plant, named after Lewis of Lewis and Clark fame and a terrific rock garden plant worth Googling so you know what it looks like and will want to plant them in your yard. The trick to growing them and keeping them going year after year seems to be keeping them from sitting in water. They are rock garden plants, after all, and can be found naturally in screes, which are essentially patches of fast draining pebbles.

In the vernacular, Lewisias don’t like wet feet. I should add they don’t like to have their leaves rest on damp soil either. So, plant them in a very well draining soil which should have sand and very small pebbles. As for protecting the rosettes of leaves, put some of the pebbles or small stones under them to lift them off the soil.

OK, here is an interesting one: “Why are my delphiniums so short? They were planted last year and they should be head high, but are only about two feet tall and in bloom right now.”

I include this question because the reader didn’t include a picture. It always helps to do so when asking a question about a plant (particularly when the question is “what is this plant?”). It also helps to send the name from the label if you kept it, as noted.

In this case, without seeing the size of the flowers, I can only guess at the cause. One is that the reader didn’t buy “Pacific Giants” and ended up with one of the many dwarf variety of delphiniums. These usually don’t grow taller than 30 inches and are often confused with the Pacific Giant types as they sport the same colors. Again, consult labels, folks. I see a theme here.

A second reason for short delphiniums may be that they have not been thinned. Over the years delphiniums form clumps and the flowers and stalks coming up smaller as the plant roots divide the goodies amongst an ever-growing tribe of stalks. The solution is to either thin the number of stalks in the very spring (when you are out there hit those delphiniums), or dig up and divide clumps every five years or so. Do this in the very early fall.

Finally, here is a complaint about rhubarb. Specifically, the question is why plants don’t get big like the neighbor’s and everyone else’s?

I am really an expert on growing rhubarb having eaten rhubarb almost every morning of my life until I was 18 and left home. As everyone knows, rhubarb needs great soil. It is a very heavy feeder as it would need to be to grow so large (see “Teaming With Nutrients!”) and needs lots and lots of rich, organic matter in the soil from which to draw nutrients for all its fabulous growth.

Ah, but everyone knows this, so the other more common reason for small plants is probably the cause; rhubarb plants should not be harvested the first year of growth. They need those big leaves to produce the sugars needed for growth above and below ground. And evaporation from the bottom of these leaves is what drives the uptake of nutrients. They probably shouldn’t be harvested the second year either, but a few stalks are allowed just to keep gardeners happy. In sort, if you start to harvest too much, too early in the plant’s life, you will never get large plants.

JEFF’S ALASKA GARDEN CALENDAR

Rhubarb: Time to start to wrap up the harvest and let the plant grow a bit undisturbed.

Radishes: Harvest all you have and start over.

Tomatoes: First ones should be ripe by now. Pollinate if you don’t have natural pollinators. Vibrate plants. An old electric toothbrush works great.

Willow Garden Club Tour: Saturday, July 26, 2014, 10 a.m. - 4 p.m. Meet at Willow Community Center for maps: Mile 69.8 Parks Highway at 9:45 a.m. (Plant Sale at WGC begins at 9:15 a.m.) Lunch is from 11:30 - 1 p.m. at Nancy Lake. Please bring a sack lunch. Tour of gardens will resume at 1:30 p.m. For more information email willowgardenclub@hotmail.com or call 495-6034.

Coyote Garden Tour (Les Brake): Saturday, July 26, 10 a.m. to 5 p.m., Sunday, July 27, noon to 5 p.m. Mile 71 Parks Highway; turn right on Willow-Fishhook Road. Drive 7.5 miles up Willow-Fishhook Road. For further information about Coyote Garden Tour call 495-6525. (Suggested donation $7)

Jeff Lowenfels is co-author of "Teaming With Microbes" and author of "Teaming With Nutrients." Contact him on his website at teamingwithmicrobes.com.