A Perennial Quest: What to Plant Now?
This may prove to be the year of the perennial. Perennials are suddenly everywhere, with offers even arriving in the mail.
“A complete garden--designed for busy people,” the offer states. It’s an intriguing idea and quite common in England where entire preplanned perennial gardens are sold through the mail. But even though the computer-generated letter says the “plants will thrive in your California climate,” perennial gardens are not quite that easy to buy, plant or build in this part of the country.
What Is a Perennial?
For the uninitiated, what are called perennials in California are--more or less--plants that live longer than an annual but are not quite as sturdy as a shrub. For those who wonder what all the fuss is about--why everyone is suddenly talking about perennials--it is because they are so valued for the variety of shape and color that they add with their flowers or their dramatic foliage.
With spring starting Sunday, this is the perfect time to discover perennials and to try planting some of these fascinating plants.
True perennials, or herbaceous perennials, generally die completely to the ground each winter, but in California’s mild climate they might not. To add some confusion, we grow many plants as perennials that are actually something else, most often a small or tender shrub.
In addition, we grow some perennials as if they were annuals, planting them each year and pulling them out at the end of their season. In the rest of this country and in England, they only grow the true herbaceous perennials, which is why information on perennials is often misleading at best.
Until this year, finding perennials at nurseries was the hardest part of starting a perennial flower garden, but this year a good selection can be found at most nurseries, and some have a selection that is really remarkable.
You may even find some at nurseries that you will not find in horticultural reference books, and planting any of these is guaranteed to be a real gardening adventure.
But perennials of any sort are an adventure because every one is different. Scan the chart on Page 4 and you will see that they flower at different times and at different heights. Unlike annuals, they do not flower all at once, so it takes time and experience to learn how to use them, which is part of the adventure.
Look at them at a nursery and even in their little pots you will see that they all look remarkably different. What looks best with what? Should I put something with gray leaves next to something with yellow or pink flowers? You can spend a lifetime tinkering with a perennial garden.
Should you be about to say, “Well I think I’ll just stick with my marigolds,” I quickly add that many perennials are as easy, or easier, to grow than a marigold and some of the best and easiest--a beginner’s selection--appear in the chart on Page 4.
Part of the Adventure
Note, however, that even these differ remarkably in culture. Learning how to grow them is also part of the adventure, perhaps the most satisfying.
Don’t let this scare you away. A lot of gardeners have been intimidated by phrases like “when to cut back” or “how to divide,” but these techniques can be learned by trial and error.
Most true perennials need to be cut back and, in time, divided. They come from climates where, to survive winter, they die to the ground, but in the mild California climate, we cut them back instead, much as we stick tulips bulbs in the refrigerator to simulate winter.
The champion tool for cutting back perennials is actually made for edging the lawn--the Corona No. 5 shear--long enough and hefty enough to cut a bunch of stems at once.
Be aware that not all perennials sold as such should be cut to the ground this way. Remember that some are not true herbaceous perennials, and these are usually just tidied up. If you’re in doubt, leave it alone and see if it dies back or not.
(Those that do die back are good choices for those gardeners who have immigrated to places such as Valencia, where winters are much colder than they are in the L.A. basin.)
Division is necessary because most true perennials grow as spreading clumps. If you look closely at a true perennial, you will see that what appears to be one plant is actually a number of smaller plants growing together. As they grow ever wider, they so totally deplete the soil beneath them that the center of the clump begins to fade. At this point, you dig it up and then pull the clump apart or slice it apart with a sharp spade.
Most serious perennial gardeners keep a flat-blade spade sharpened with a coarse file just for this purpose.
The old center of the clump is usually discarded and the younger outer growth divided into smaller pieces and replanted. Extra divisions can be given away, and most gardeners get pretty good at swapping their extras with another who might have some perennial they don’t. Most of this dividing (and the swapping) is done during winter.
Because perennials use a soil so heavily, it is very important to thoroughly prepare a soil before planting. The idea is to make it as rich as possible by adding fertilizer and organic amendments (the kind sold by the bag at nurseries, usually a mix of specially treated barks and sawdusts). These are mixed in with a spade, spading fork or a tiller and the result is a fluffy, rich soil that will sustain a perennial for a number of years.
When it is time to dig and divide, the soil can be renewed by adding still more organic material and fertilizer. A well-prepared soil is also a lot easier to dig in, so the perennials are easier to dig up and divide, or just move about.
This is one advantage of using perennials--they are easy to dig up and move. If you don’t like how they look where they are growing, or if they grow too tall, you can dig them up and move them somewhere else.
The 13 perennials listed in our chart are more than enough to build a garden. How you mix these perennials is a matter of taste, but I’ll pass along a scheme that has always worked for me.
Roses Carry the Show
I always include roses with my perennials, because I think they look better mixed with other flowers (can’t see the bare lower branches) and because they bloom so often that they help carry the show, should most of the perennials be temporarily out of bloom.
My basic rules are:
1. Let one part of the color spectrum predominate.
2. Never plant fewer than three of anything.
3. Repeat yourself.
In the planting plan on Page 3, note that there are three or five of every plant. There is no point buying just one, because it will not make enough of an impact. Note also that there are three roses anchoring this planting. If you don’t use roses, use some kind of permanent plant with a bushy shape, even a small shrub. For instance, in the shade, azaleas could be substituted.
Note also that a plant that appears at one end of the garden reappears somewhere at the other end. This helps provide a sense of continuity and the repetition adds to the impact.
Simplicity, Harmony
To keep things simple and harmonious, the colors are all from the blue-red end of the spectrum--reds, pinks, blues, lavenders and purples. Another scheme would be to use only yellows, oranges and purples.
In fact, many gardeners more expert than I think that there are only these two color groups and that one should not be mixed with the other except if used as an accent. One soft yellow perennial would probably enliven the scheme shown here.
And don’t forget the foliage. Many perennials have leaves as handsome as the flowers, and gray foliage in particular adds much to the look of the garden.
Beyond this, I try not to have all the tall plants in the back, but let a few choice ones (the delphiniums in this case) move up front, which adds to the drama. In general, however, the plants get taller toward the back.
Space, Diversity Important
Notice that you cannot fit all of this into a narrow little garden bed. I had to dig up 2 feet of lawn to get the necessary 4 feet of width, and another foot would have been even better. The wider the bed, the more opportunity you have to stage and the more variety you can fit in. This allows you to plant things that bloom at various times of the year, one in front of the other. And that actually is one other rule I try to follow--don’t only buy plants that are in flower or you will end up with plants that flower all at the same time. Make sure you buy some that flower at other times to prolong the show.
In the chart we tell when these perennials will most likely be in bloom and in the plan we show diagonal lines running through those that flower in late summer or fall. Be careful not to clump all later-flowering perennials together, but spread them out so the whole garden appears to be in flower when they are.
(Diagonal lines running the other direction indicate a shady corner of the perennial bed, and there are some very good perennials for these shady corners.)
Dare to Experiment
In addition to the plants listed in the chart, don’t be afraid to plunge in and try the new ones appearing at some nurseries this year. I’ve got a driveway full. I don’t know what Knautia arvensis , Hesperis matronalis or Lobelia siphilitica will look like (I can barely pronounce their names), but Centaurea montana turned out to have flowers shaped like exploding stars. They are almost a true blue and have gray foliage to boot.
I also make sure to leave some room for annuals and bulbs, and I always mix herbs in with the perennials, because they add fragrance and look right at home.
And don’t forget about some of the most tried and true perennials, perennials that have been part of California gardens for so long that we hardly think of them as such--agapanthus, bergenia, bearded iris, calla lilies and day lilies to mention just few. Agapanthus are a must because they will absolutely astound any visiting English or Eastern gardeners (an opportunity not to be missed), because they find them so hard to grow.
A BASIC PALETTE OF PROVEN PERENNIALS: YELLOW, ORANGE, PINK AND BLUE, AND GRAY FOLIAGE TOO What it is: Achilleas or yarrows, comes in a great variety of heights, from over 3 feet to under 6 inches. Flowers are flat-topped and there are bright and soft yellows, pinks and lavenders and whites. Foliage is low and ferny. When it blooms: Summer and early fall. Best way to buy: Small kinds (often available in the herb section) best from small six packs. Others from 4-inch pots or gallon cans. Know the height of what you are buying. How to plant: Space small kinds about 6 inches apart, tall kinds a foot apart. They spread by underground runners and fill in quickly. Demand full sun. When to cut back: Cut flower spikes to the ground after flowering leaving only the foliage at the base (or cut and dry--they make good dried flowers). When to divide: Every few years, clumps should be dug up and divided, split apart with a spade and restarted in renewed soil. Save the younger, outermost plants and discard the old center. What it is: Anemone japonica,the Japa nese anemone, grows as a slowly spreading clump of maple-like leaves about 2 feet tall. Flowers are airy, colored pink, lavender, or most common, white, on stems 3-4 feet tall. When it blooms: Fall or late summer. Best way to buy: Buy in 4-inch pots or gallon cans. In this case, the gallon cans are the better buy since plants will bloom first year in the ground. How to plant: Plant in partial shade in a woodsy soil enriched with organic amendments. Space 2 feet apart. When to cut back: Cut completely to the ground in December to get rid of flower stalks and leaves which tend to turn brown at tips during winter. When to divide: Divide in winter only if you need more plants or should clumps stop flowering. These are pretty permanent plants. Dig up and pull apart,
then replant. What it is: Aquilegia,or columbine, have delicate, airy, gray-green leaves and flowers that look like shooting stars. McKana Giants are most common and may be any shade or mix of red, yellow, pink, lavender or white. Stand 2-3 feet tall. When it blooms: Late spring into summer. Best way to buy: Plant from small six packs, 4-inch pots or gallon cans though the gallons will be the first to flower. Small plants may take a full year to flower. How to plant: Despite the woodsy appearance, columbines need full sun. Space about 18 inches apart. When to cut back: Cut back flowering stems when they finish. If plants look ragged by December, cut almost to ground for a fresh start. When to divide: Clumps cannot be divided, last about 2-3 years but then should be pulled out and replaced. What it is: Chrysanthemum maximum,the good old Shasta daisy, has white flowers, full and double on the varieties Aglaya and Esther Read, single on Alaska and the new compact Snow Lady. The latter grows only a foot tall, others to 18-24 inches. Leaves are low to ground, dark green. When it blooms: Peak bloom is during June, early July. Best way to buy: These are a good buy in small six packs since they grow fast and bloom quickly. How to plant: Space about a foot apart in full sun. When to cut back: Cut flowers back to ground after they finish. When to divide: Shasta daisies spread slowly to form good-sized clumps but it’s best to dig up the clumps every 2 years in January, saving the best plants. Discard the old centers of the clump. Some gardeners think it easier to simply start over every few years. What it is: There are many Coreopsis but the best is one called Sunray that makes a dense ball of foliage about 18 inches tall by 2 feet across that is covered with brilliant golden flowers. When it blooms: All summer and fall. Best way to buy: Best grown from seed (it is one of the easiest and fastest), but also good from any size container. How to plant: Plant in full sun and space 2 feet apart. When to cut back: Cut flowers off as they finish. Even though the plant looks fine in winter, cutting it completely to the ground in January gives it a fresh start resulting in more flowers the
next year. When to divide: Dig up clumps every few years in January, before they get too large, cut back and divide into smaller pieces and replant. Give the extras to friends. What it is: Dianthus,or pinks, make low cushions of gray-green foliage that look best at the front of the flower garden. Flowers in many shades of red, pink, lavender and white on stems about a foot tall. They are related to carnations and most are fragrant. When it blooms: Some flower all year, but the peak for most is in spring. Best way to buy: Best from 4-inch pots or gallon cans. How to plant: Space a foot apart for quick fill though they can spread to 2 1/2 feet, in full sun. When to cut back: Though it is tedious (there are so many), cutting off the dead flowers will encourage more. Hedge shears speed up this job but also cut off
some buds. When to divide: Dianthus can’t be divided and they only live 2-3 years but they are easy to restart from tip cuttings placed in a pot filled with wet sand and covered with a plastic bag. Best time is early spring. What it is: Delphiniums are the cathedrals of the perennial border, towering to 6 feet in the case of the tall Pacific Giant types, or 3-4 feet in the case of those called Blue Fountains. Flowers are the best shades of true blue, lavender, pink, white. When it blooms: The peak is in May and June, but if cut back they will rebloom in late summer. Best way to buy: Blue Fountains are best bought in small six packs or 4-inch pots in the spring; the Pacific Giants do best from 4-inch pots planted in the fall, but will still flower if planted in spring. Planted late, flowers will be shorter and not as sturdy. How to plant: Space Blue Fountains a foot apart, Pacific Giants 18 inches apart. Both need full sun. For the best flowers dig an 18-inch-deep hole, mix organic amendments into the soil and put a tablespoon of a granular fertilizer in the very bottom. The Pacific Giants will need staking. When to cut back: When flowers are finished, cut them back so only 2 leaves remain on the stem, then fertilize and water well and they will resprout at base and flower again. When to divide: Though they are true perennials they do not do well the second year in California so take them out in the fall and begin anew. What it is: Heuchera,better known as cor al bells, make tight little clumps of round leaves under a foot tall. From these spring wands of tiny coral, pink or white flowers that are about 18 inches tall. When it blooms: Late spring and early summer. Best way to buy: Can be started from small six packs, 4-inch pots or gallon cans; the bigger the container the sooner you get flowers. Plants grow fairly slowly. How to plant: Plant in sun or a little shade. Space about 18 inches apart or less and give plenty of water. When to cut back: Cut off spent flower spikes but not leaves. When to divide: Can be divided by digging up and gently pulling apart. Sometimes pieces must be snapped off but be sure to include some roots with each piece. Divide only if too large or if center begins to die out. What it is: Liatris,gayfeather, or blazing star, makes a small clump of narrow leaves which expand into 30-inch tall spikes of brilliant purple or white flowers that look like fuzzy cattails. It’s a favorite of florists. When it blooms: Flowers in late summer and early fall, when little else does. Best way to buy: Look for it in the spring in the bulb bins at nurseries because it is most commonly sold as a small round tuberous rootstock. Also found sometimes in 4-inch pots or gallon cans. How to plant: Plant tubers 2-3 inches deep about 6-8 inches apart in full sun. Make sure to mark their location with a garden stake. Plants from pots should be spaced about a foot apart. When to cut back: After flowering, cut completely to the ground because the whole plant goes dormant for the winter. Mark the location with a stake so you don’t dig it up by accident. When to divide: Don’t disturb the clumps until they begin flowering poorly. At that time, dig up after flowering, discarding old partially decayed root stocks and replant in
renewed soil. What it is: Physostegia,sometimes called false dragonhead, is one of the easiest to grow, spreading slowly to form stands several feet across. Leaves appear in early spring and slowly grow to become flower spikes covered with purple or white flowers. When it blooms: Flowers late in summer or in fall. Best way to buy: Best from gallon cans or 4-inch pots. Gallon can size can often be divided right away to get many more plants. How to plant: Space plants about a foot apart in full sun. Plants spread over the years to form colonies. When to cut back: Cut flower spikes completely to the ground after flowering. When to divide: Plants are easy to dig up and separate into many new plants. This becomes necessary in time to keep them in bounds. It is best to do this right after flowering, even before the old stalks are cut off. What it is: There are many Salvia but the most commonly available perennial is the so-called blue bedder,Salvia farinacea,which is actually a royal purple, though there is also a handsome white. These grow quickly into an 18x24-inch wide mound. When it blooms: Most of spring and summer and into fall. Best way to buy: Start from small six packs, 4-inch pots, or even gallon cans though the pot is the best bet. How to plant: Space about 18 inches apart for quick fill; needs full sun. When to cut back: Cut off flowers when they have peaked and plants will come back into flower. When to divide: Though it will last several years, this salvia is usually planted as if it were an annual, being pulled out by winter and restarted in early spring. What it is: Stachys,or lamb’s ears, is the darling of the perennial bed, growing fast to cover 3 feet of ground but staying under a foot tall, with leaves that are silver-gray and as soft as a lamb’s ear. Spikes of small pink flowers grow to 18 inches tall. When it blooms: In early summer, but are not spectacular. Best way to buy: Best from 4-inch pots. Very fast grower. How to plant: Space plants about 2 feet apart. They grow quickly and will take some shade but look best in full sun. When to cut back: Cut off flower spikes after they bloom. When to divide: Lamb’s ears last perhaps 2-3 years at most, but they can be quickly replaced by new plants. A good idea is to separate some pieces by digging them out with a trowel and growing them in pots in preparation for that day. What it is: Veronica,or speedwell, is an other large group where only a few are found at nurseries. Most grow to 18-24 inches and have dense, slender spikes of small flowers that are shades of violet-blue. Shirley Blue is one of the best. Plants spread very slowly to 2 feet across. When it blooms: The first flowers come in spring and if these are cut back, they flower again in summer, and even in fall. Best way to buy: Gallon cans are the best choice, followed by 4-inch pots. How to plant: Plant about 18 inches apart in full sun. When to cut back: Cut the whole plant to within inches of the ground after each flowering and it rebounds almost immediately. It is possible to have three distinct blooming periods each spring and summer. When to divide: Plants can be easily divided to get more by digging them up and cutting apart with a spade--each clump is actually dozens of little plants. Division is only necessary, however, after several years when center stops flowering.
