The only thing Dutch about Dutch iris, Iris X hollandica, is the location of its breeding. It is a hybrid of various iris from Morocco, Algeria, Spain and Portugal. It became popular originally for the cut flower industries of Europe. It did not become available to American home gardens until the 1950s. Even now, it remains somewhat rare for home gardens.
Unlike most common iris, Dutch iris grows from bulbs rather than from fleshy rhizomes. They produce narrow leaves that stand about a foot and a half to two feet tall. Their big iris flowers bloom about May, just below the tips of their foliage. Floral color is primarily blue but can be yellow or white. Flowers lack fragrance. Bulbs are conducive to forcing.
Like other spring bulbs, dormant Dutch iris bulbs should go into their garden about now. Bulbs can be set about six inches apart, and about four or five inches deep. If nurseries do not market enough varieties, more are available online. ‘Imperator’ blooms dark blue. ‘Wedgwood’ blooms light blue. ‘Yellow Queen’ blooms pastel yellow. ‘White Excelsior’ is shorter and blooms white. Mixtures of a few varieties are available.
Autumn is time for planting. This does not apply to all plants, but is certainly relevant to spring bulbs. Many have been available from nurseries for a while already. They all are dormant by late summer or early autumn. So, they are unaware of their relocation from their farms to home gardens. They will learn about it when the resume growth next year.
Actually, though, spring bulbs begin growth sooner than that. It merely does not become visible until foliage emerges above its soil after midwinter. Roots begin to disperse when their soil is dampened either by irrigation or rain. Growth is initially slow because of cool autumn and winter weather. It accelerates as weather warms, as spring replaces winter.
Spring bulbs know how the seasons change from temperature. They adjust their growth accordingly. They know that they can disperse roots early. They delay other growth until after a specific duration of cool weather, or vernalization. From the nursery, many spring bulbs are prechilled, or already vernalized. That is why they are so conducive to forcing.
Summer bulbs prefer later planting because they do not need vernalization to bloom. In fact, some are susceptible to rot if they must overwinter in cool and damp soil. They are more resilient once established, after their first summer. These include gladiola, canna, calla, dahlia, tuberous begonia and most lily. They become available after spring bulbs.
Because winter is so mild here, some spring bulbs are unreliable after their first season. They may not receive the degree of chilling, or vernalization, that they require. Hyacinth and tulip, for examples, may bloom only once for their first spring. Afterward, they might not be reliably perennial. Dutch iris and Dutch crocus are only somewhat more reliable.
Freesia and narcissus, including daffodil, are some of the most reliable of spring bulbs. Within favorable conditions, they can multiply and slowly migrate. Grape hyacinth might actually become slightly invasive. Ranunculus and anemone may be reliably perennial, but may not bloom much. Bluebells are supposedly very reliable but remain uncommon.
This is not a typical warm season annual. Nor is it a typical cool season annual. Actually, there really is nothing typical about Anemone, Anemone coronaria. It is a spring bulb that is really a tuber that goes into the ground in autumn. Yet, it is more available blooming in four inch pots in spring. It functions as a spring annual because it blooms as winter ends.
Anemone are quite diminutive. Basal rosettes of only a few deeply lobed leaves are less than eight inches tall. Flowers of taller sorts stand above their foliage, but less than a foot high. They can bloom between March and May. Nursery stock blooms earlier than plants that grow from bulbs in a garden. Growth eventually slows as weather warms in summer.
Floral color ranges through red, white, blue, pink and purple. Flowers mostly have black centers. White flowers may have green centers. Some varieties bloom with semi-double or double flowers, or flowers with two colors. Most flowers are about three inches wide or slightly wider. Anemones are good cut flowers; but cutting deprives the garden of bloom.
Some of the most familiar flowers to bloom in the earliest of spring get planted now as bulbs. They sit and wait in the garden to finish their dormancy, perhaps get a bit of a chill through winter, and get an early start to their bloom cycles as soon as weather permits. Because winters are so mild here in the Santa Clara Valley, some do not even bother to wait for spring, but are instead happy to start bloom before winter ends.
Bulbs become available in nurseries when they can be planted. Those that are not available yet will become available when it is time to plant them for later spring or summer bloom. The first to become available are generally the first to bloom; although bearded iris seem to know when they want to bloom, regardless of when they get planted.
As long as they do not get stored too long or get planted too late, bulbs do not need to be planted immediately, and actually extend their performance if planted in phases. The earliest phases to get planted will bloom earliest. Phases of the same bulbs planted a few or many days later should bloom about the same amount of time later.
With proper planning, later phases bloom as earlier phases finish. For example, because crocus flowers do not last very long, different phases of bulbs can be planted only a few days or a week apart, so that more flowers start to bloom in time for earlier flowers to fade. Freesia flowers last a bit longer, so different phases can be planted two weeks or so apart.
Narcissus and daffodil bulbs are not so discriminating about how deeply they get planted, so various phases can be put in the same spots. As long as they do not get planted too deep, the earliest phases can be planted deep and covered with only a bit of soil, so that later phases can be planted above. If similarly covered with only a shallow bit of soil, later phases of the same bulbs can be stacked, as long as the last and shallowest phase still gets planted deep enough.
Not many bulbs are actually real bulbs. Most are corms, tubers, rhizomes or tuberous roots. They all do the same thing though; store resources through dormancy to sustain quick bloom as weather allows. Although many bloom reliably only once in their first season, some naturalize to bloom at about the same time each year. Tulips are capable of naturalizing, but rarely get enough chill in winter to bloom after their first season.
Anemone (windflower), hyacinth, lily, rananculus, tulip and small colorful callas are the less reliable of spring bulbs after their first year. Crocus, freesia, hymenocallis and harlequin flower can be more reliable if they get what they want. Grape hyacinth, narcissus, daffodil, watsonia, bearded iris and the old fashioned white callas are the most reliable of bulbs that get planted about now.
Most flowers that must attract pollinators do so with either color or fragrance. Hyacinth is an exception that does both. It is as fragrant as it is colorful. Its intensely rich fragrance is supposedly comparable to that of lilac. Its floral color range includes many hues and tints of most colors but green. It blooms for very early spring along with many types of daffodil.
Dormant hyacinth bulbs go into their gardens about now, but do nothing until after winter. They then bloom with several narrowly tubular florets on stoutly cylindrical trusses. Each floral stem is only about half a foot tall, but stands above its narrow leaves. Foliage lasts for merely two months or so after bloom. It eventually withers with the warmth of summer.
Hyacinth crave rich soil, sunny exposure and regular irrigation after the winter rain stops. They can work nicely with cool season annuals, such as pansies or violas. They appear and bloom just before pansies and violas finish their seasons. Alternatively, hyacinth are conducive to forcing. Unfortunately, they like more winter chill than they experience here after prechilling.
Summer bulbs, such as canna, calla and dahlia, can wait until spring. They do not enjoy winter chill during their dormancy like spring bulbs do. Spring bulbs become available at nurseries now because this is the time to plant them. They wait patiently for winter to end before blooming. A bit of winter chill actually helps them to maintain their strict schedule.
That certainly does not mean that their strict schedule is not adjustable. Most early bulbs prefer interment into their shallow graves within weeks of Halloween. However, they can wait as late as New Year’s Day. This allows for successive planting, which prolongs their ultimate bloom. Early planting promotes early bloom. Late planting promotes late bloom.
Most spring bulbs from nurseries are prechilled because winters are relatively mild here. They are therefore less reliant on significant winter chill. However, some of such bulbs in several of the milder climates may bloom only once. They lack the winter chill they need to bloom for subsequent springs. Avid garden enthusiasts compensate with refrigeration.
That requires major diligence, though. Most who enjoy gardening do not want to dig and refrigerate dirty spring bulbs. Consequently, most who grow them enjoy them as annuals or disposable perennials. Unfortunately though, spring bulbs do not bloom for very long, and are not inexpensive. That is why they are not as prevalent here as in other climates.
Freesia and narcissus, including daffodil, do not need much chill. They can settle in and bloom for many years after their initial planting. Ranunculus and anemone may not need much chill either, but are less likely to regenerate from year to year. Dutch iris and Dutch crocus are unpredictable. They might become reliably perennial, but may not cooperate.
Tulip and hyacinth may be more disappointing, since they require significant winter chill. If they can not experience such chill naturally from the weather, they require refrigeration. Otherwise, they bloom only once for their primary season, and only after prechilling. Yet, both are among the most popular of spring bulbs. Their blooms are simply too appealing.
As diverse as they are, popular varieties are a minority of countless hybrids of the genus. Most common and popular hybrid tulips qualify as the neo-species of Tulipa gesneriana. In other words, they are not an actual species. Most but not all are descendants of Tulipa suaveolens. More sustainable varieties of simple species are becoming more available.
The most popular of tulip are early spring bulbs that went into their gardens last autumn. Floral color ranges through pink, red, orange, yellow and white, mostly with dark centers. Their basal foliage is rather light green or perhaps almost grayish, with a rubbery texture. Most tulips stand singly on straight stems about a foot tall, but some can grow a bit taller.
Tulip bulbs enjoy organically rich soil with regular irrigation throughout their bloom cycle. They should get all the moisture they want from rain through their winter dormancy cycle. Tulip prefer a bit of chill in winter, so may not be as reliably perennial here as elsewhere. They are most spectacular in herds or large beds, but mix nicely with other spring bulbs. Simple tulips are among the most popular of cut flowers.
Even though bulbs for harlequin flower, Sparaxis tricolor, are no longer commonly found in nurseries when it is time to plant them in autumn, naturalized bulbs are somewhat common in some older gardens. Where winters are mild and soil does not get too dry and compacted, they are happy to slowly multiply and bloom every spring. They seem to be blooming a bit early this year, since they typically wait until later in spring. The upright narrow leaves resemble those of gladiolus, but get no taller than a foot. Each flower stems rises a bit higher to display a few flowers that are about an inch and a half wide. Each flower has a yellow center surrounded by a narrow rusty brown pattern, which is also surrounded by a third color; which is orange, red, pink or purple.
If their bulbs were planted when they became available as summer evolved into autumn, Tazetta Narcissus and their hybrids should begin to bloom about now, a bit prior to related daffodil and jonquil Narcissus. In cooler winter climates, bloom must wait until early spring. The most popular variety, ‘Paper White’ blooms with about five or six small clear white flowers clustered on top of foot tall stems surrounded by vertical and somewhat rubbery, narrow leaves. Other varieties have white or yellow outer petals, known as the ‘perianth’, or orange or white centers, known as the ‘cup’. All are good cut flowers that are quite fragrant.
Because it is best to leave narcissus foliage to yellow and abscise (shed) naturally after bloom and as weather gets warmer, ground covers that are deep enough to conceal their deteriorating foliage are practical companions. (For example, deteriorating narcissus foliage can be stuffed under healthy English ivy, where it can be hidden without being removed.) Ground cover also keeps the soil from being bare during summer and autumn dormancy.
Mature clumps of narcissus bulbs only need to be dug and divided if they become so crowded that they do not bloom as much as they should. They are easiest to dig immediately after foliage dies back and lies on the ground, when they are dormant but still easy to find. Dug bulbs should then be stored in a cool dry place until it is time to plant them late in summer. Bulbs should be planted about five inches deep and about five to eight inches apart, with good sun exposure. The largest bulbs with multiple buds (known as ‘noses’) bloom most abundantly.
If they are happy in their location, narcissus easily naturalize, even if they do not get divided occasionally. They get most of the water they need from rain, since they are mostly dormant before dry weather in summer. Gophers and deer do not bother them.
