Autumn Planting Of Spring Bulbs

Spring bulbs start now.

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.

Hyacinth

Hyacinth are both colorful and fragrant.

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.

Bulbs For Spring Start Now

Ranunculus will bloom for early spring.

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.

Tulip

A single tulip flower seems lonely.

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.

Harlequin Flower

‘Tricolor’ (obviously) means ‘three colors’.

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.

Narcissus

Daffodil are a type of Narcissus.

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.

Ranunculus

Ranunculus blooms several months from now.

The shriveled and dried tuberous roots of Ranunculus are not much to brag about. They look more like dehydrated mini calamari than dormant and viable spring bulbs. Yet, they somehow bloom as soon as the weather warms enough after winter. Although they need no vernalization, they need time to grow. Bulbs should be into their garden by December.

Alternatively, small budding plants will be available from nurseries after winter. They are too big for cell packs, so are mostly in four inch pots. Larger one gallon plants often have shabby foliage. Although popular as annuals, Ranunculus can be reliably perennial like other bulbs. They are less susceptible to rot if dug and stored while dormant for summer.

Ranunculus bloom is white, yellow, orange, red, pink or purple. The plump flowers have many papery and densely set petals, like small peonies. They typically stand less than a foot high, and may be only half a foot high. Their finely textured basal foliage stays even lower. It resembles parsley, but is a bit more substantial. It shrivels during warm weather.

Spring Bulbs Benefit From Vernalization

Spring bulbs vernalize with winter chill.

Spring bulbs obviously bloom for spring. Less obviously, they vernalize with winter chill. They are seasonable about now because this is when they should get into their gardens. Many prefer to be interred into their shallow graves by Halloween. Many can wait as late as New Year’s Day. If too much later, some may not experience enough chill to vernalize.

Planting spring bulbs can be ungratifying because there is nothing to see afterward. After all, they are dormant at the time. They lack foliage or any other parts to extend above the surface of the soil. They seem to remain inactive until they bloom as winter succumbs to spring. However, between now and then, they will secretly reset before resuming growth.

Vernalization is how many spring bulbs finish their previous season and begin their next. They know that it is winter after they experience a particular duration of a particular chill. By then, they should have finished all growth of the previous season. Afterwards, all new growth and bloom is for the next season. It is how they know to bloom on time for spring.

Dutch iris, freesia, ranunculus, anemone and common narcissus do not need much chill. Tulip, hyacinth, crocus and a few narcissus and daffodil do. Some bulbs that benefit from it get a prechill treatment before coming to nurseries. Prechilled tulip and hyacinth bulbs are sadly unlikely to bloom after their first year. They prefer more chill than they get here.

Otherwise, many spring bulbs are supposedly reliably perennial. Naturally, actual results may vary. Anemone can survive for many years, but might bloom only rarely. Ranunculus may be less perennial, but may also bloom better while it survives. Dutch iris and crocus are unpredictable. Freesia and simple varieties of narcissus are more reliably perennial.

Technically, some spring bulbs are not bulbs. Ranunculus and freesia, for example, grow from corms. Nonetheless, almost all spring bulbs bloom only once annually. Succession planting can prolong bloom. It provides subsequent phases to begin bloom as preceding phases finish. However, phases of reliably perennial bulbs synchronize after first bloom. Summer bulbs and bulb-like plants are seasonable later.

Ranunculus

These grew from formerly small and shriveled clumps of tuberous roots.

It is hard to imagine how the small shriveled clumps of tuberous roots of ranunculus, Ranunculus asiaticus, planted last autumn can produce such bright pink, red, orange, yellow and white flowers between late winter and early spring. The two or three inch wide, semidouble or double flowers stand about a foot high, just above their soft deeply lobed foliage. Those of us who did not get ranunculus in the ground last autumn can find blooming plants now. Ranunculus want to be in full sun, in rich, well draining soil.

Deadheading (removal of fading flowers) promotes subsequent bloom; but the season is rather short. Foliage will soon be turning yellow, and will eventually die back. If not watered too much, dormant ranunculus can survive through summer, but should be dug and stored in a cool dry place until next autumn if they are in pots or areas that will get watered regularly.