Q I hope you can give us some suggestions as to what is best to plant on a hillside in poor soil and is not liked by gophers. Red apple iceplant (Aptenia hybrid) seems to do well but is eventually eaten by gophers. We do have ornamental asparagus growing, but I don’t particularly like it, even though the gophers don’t like it either.
— Gerda McKeehan, West San Fernando Valley
A Well, before moving on, you have already helped in our eternal quest of solving the gopher conundrum just by mentioning the fact that gophers do not find ornamental asparagus (Asparagus densiflorus ‘Sprengeri’) appetizing. You say you don’t like it, and I respect your opinion, but there are surely gopher-challenged folks with hillsides who may take a fancy to this indomitable plant.
Ornamental asparagus is considered highly attractive by some on account of its billowy foliage, consisting of long arching leaves made up of tiny, needle like leaflets that would appear to be soft to the touch. Its appearance is deceiving, however, since it is actually somewhat thorny and makes grooming it a challenge if you are fanatic about foliage that turns yellow and then brown.
You need gloves to remove this foliage without getting stuck.
Yet, ornamental asparagus exhibits considerable drought tolerance once it gains a foothold and will happily scamper over a hillside without human assistance. It propagates both by underground rhizomes and by red berries, which are preceded by clusters of white flowers.
Incidentally, as long as we are on the asparagus subject, edible aspargus (Asparagus officinalis) has highly fibrous roots that, while nibbled by gophers, are not overly appetizing to these incorrigible rodents. Gophers are much fonder of fleshy roots and bulbs so that existence of a local gopher population should not be a barrier to planting asparagus of any description.
The best discussion I have found on plants resistant to gopher dining proclivities has been generated by Dr. Thomas Osborne and his website, tastylandscape.com. When you get there, click on the “pests/treatment” tab and scroll down to and click on “gophers.”
There, you will find three lists of plants accompanied by testimonials from Osborne and his readers: “gopher-resistant plants (from direct experience), reportedly gopher-resistant plants (that I have no direct gopher experience with — yet), and plants that have been said to be gopher-resistant and actually are not.”
When scanning the list of gopher-resistant plants, one quality common to most of them is a strong smell, whether pleasant or unpleasant. Among the most gopher-resistant species, you will find rosemary, lavender, Mexican sage (Salvia leucantha), zonal and scented geraniums, lantana, eucalyptus, pine, rockrose (Cistus spp.) and society garlic. Curiously, although society garlic and common edible garlic belong to the same genus (Allium), society garlic is gopher resistant while edible garlic is not.
An important aspect of this discussion concerns the network of tunnels gophers construct. The word gopher is derived from the French gaufre, meaning waffle or honeycomb, in reference to the criss-cross pattern of gopher tunnels.
At a depth of 18 inches below ground level, these tunnels can lead to root desiccation and death of any plant in the vicinity. What this means is that plants in the gopher resistant list may suddenly wilt and die but, in such cases, it would be worth investigating if the roots were consumed or simply dried up due to having grown into a gopher tunnel.
I would also surmise that lack of precipitation, notwithstanding our recent rain, may have contributed to gopher consumption of normally gopher-resistant plant species.
The presence of succulent roots would have diminished during our long drought, and so gophers may be seeking out plants with stringy or fibrous roots that they would ordinarily avoid, just as coyotes come down from the hills in search of our pets when their usual animal prey, also diminished by drought, is unavailable to them.
If you want insurance for the root system of any species planted in gopher territory, you might wish to consider constructing gopher cages from galvanized hard wire cloth (1/4- or 1/2-inch gauge). The wire cloth is available in 2- or 3-foot width, which would make a nice-sized height for a planting hole.
You still want to make sure that the top of your root ball is even with or slightly above ground level so there will need to be backfill at the bottom of the hole/cage before the root ball is placed. Yes, the roots will eventually grow through the holes in the wire cloth, but even if these roots are nibbled, the main root system will not be compromised.
If you were to plant lantana or trainling rosemary, for example, you could plant one gallon or five gallon specimens, with the roots of each in a gopher cage, several feet apart and let them grow toward one another, eventually covering the slope. It is advisable to leave 4 inches of the hardware wire above ground level so gophers cannot bypass the cage. If rabbits are a problem, leave an additional several inches of hard wire above ground to prevent them from accessing your plants.
It would be a good idea to heavily mulch the soil between plants so that weeds do not invade the area before the plants have the chance to grow together.
For more information about area plants and gardens, go to Joshua Siskin’s website at www.thesmartergardener.com. Send questions and photos to Joshua@perfectplants.com.
Tip of the week
There is an effective, nontoxic method for biological control of gophers: acquisition of an exotic pet. According to Organic Gardening magazine, you should consider “gopher and king snakes, skunks and particularly barn owls. A pair of breeding barn owls can eat from three to six gophers every few nights.”
Barn owls, which are no bigger than crows, are recognizable by their unmistakable heart-shaped, chalky white, “Phantom of the Opera” masks. They consume not only gophers but moles, voles, mice and rats as well.
Biologists have long been privy to the knowledge that March and April are the peak breeding months of both owls and gophers. What this means is that there will be plenty of prey for the owls just at the moment when they are hungriest and also have fledglings to feed.
This understanding led to the reasonable assumption that if you brought a pair of breeding barn owls into a gopher-infested area, the owls would soon rid you of your gopher problem. But this assumption was wrong.
The breakthrough in owl-gopher research was reached when it was discovered that although barn owls are found throughout the world (except the higher latitudes), they come to any area strictly by their own choosing. When you forcibly place them in a particular spot, they fly away. However, if you build a proper nesting house for them, they will appear out of the clear blue sky and become your tenants.
To build an owl house, sink a 4-by-4-inch pole 4 feet into the ground and build a nesting box to be attached at the top of the pole, which should extend to a height of 12 feet above ground level. The nesting box should be 16 to 24 inches on each side, with landing dowels, an entry hole 6 inches in diameter in front, several 5/8-inch drainage holes at the bottom, together with a clean-out panel, and four 3/4-inch air holes on the side. If placed in the sun, as opposed to under a tree, a slanted roof should be provided on the top of the box, extending several inches over the front and back to give the owls shade. Care should be taken not to place the nesting box in an area of intense vehicle or foot traffic, since owls will not visit such noisy sites. Detailed instructions for building an owl nesting box may be found at barnowltrust.org.uk or order them ready made through internet vendors, with prices ranging from $40 to $100.
If you would rather stay with a more conventional pet, a family of cats may also provide relief from gophers, which, after all, are as tasty as mice to your furry feline friends.
