Annuals Should Match The Weather

P80317Pulling out cool season annuals that are still somewhat colorful is never easy, even if they are already deteriorating. There is always the desire to stretch their season as late as possible until they succumb to warmer weather. Only a few can perform all year, or get cut back to hide below other taller plants until the weather gets cool enough in autumn for them to regenerate and bloom again.

Regardless of all the resistance, removing the annuals of a previous season relinquishes space for annuals that are appropriate to the next season, whether cool to warm season, or warm to cool season. Even if new annuals are initially wimpy relative to the older annuals that were removed, they should proliferate and bloom better than lingering unseasonable annuals would if not removed.

Timing is somewhat important. There is no point in removing cool season annuals too early if the weather is still too cool for warm season annuals. However, there is no point in planting too late either. Delayed planting only delays growth and bloom. Some warm season annuals, especially those grown from seed sown late in winter, prefer to get established while the weather is still cool.

French marigold is probably the most traditional warm season annual for bright yellow, orange and bronze. Lobelia contrasts excellently with rich blue and purple, and can also be purplish rose or white. Petunia can do even more with brighter and more variable colors. Cosmos provides pastel pinks and white on taller plants. Cockscomb colors rival those of marigold, and can also be red.

Pincushion flower, annual statice and zinnia are popularly enjoyed as bedding plants, and also work well individually, behind lower bedding plants, or in planters of mixed annuals or perennials. Verbena and moss rose cascade nicely from such mixed planters. Sadly, brightly colored and formerly popular busy Lizzie (impatiens) are either rare or unavailable because of a mold disease.

Nasturtium and alyssum are warm season annuals that are often grown through winter as well. Where they are allowed to naturalize and bloom throughout the year, deteriorating old plants might need to be groomed out as they get replaced by self sown plants. New nasturtium should be sown as seed, instead of planted as seedlings from cell packs. Alyssum grows well by either means.

What Bulbs Do After Bloom

90403thumbNarcissus, daffodil, freesia, snowdrop, snowflake, grape hyacinth, various iris and most other early spring blooming bulbs and bulb like plants should be perennials. We plant them with the hope that the will survive after bloom to bloom for another season, and perhaps for many seasons. Some should multiply to provide more bloom over the years. Bloom is just part of their annual cycle.

Lily, crocus, hyacinth, tulip, anemone and ranunculus are not nearly as likely to bloom more than one year for a variety of reasons. Some prefer more chill in winter. Some dislike the long and dry summers. Some survive as perennials, but do not bloom again. However, in some special situations, they also can bloom annually. After spring bulbs, there will be a different set of summer bulbs.

So, what happens after bloom? After exhausting much of their stored resources on production of bloom and foliage, bulbs try to recover and regenerate resources for the following season. Most work to replace their exhausted bulbs with comparable new bulbs. They need foliage to do this, but eventually shed their foliage as their new bulbs go dormant for the following autumn and winter.

Of course, they all do this at different rates. Some smaller bulbs are surprisingly efficient, and shed their foliage as soon as the weather gets warm later in spring. It is amazing that they can store up so much in such a minimal time. Other bulbs shed slowly, as their deteriorating foliage lingers for a few weeks into summer. Foliage of summer bulbs that bloom later is likely to linger until frost.

Because it is essential to the regenerative process, deteriorating foliage can not be cut back prematurely. It is not always easy to hide either. In mixed plantings, it might be obscured by ground cover or other plants. Alternatively, warm season annuals can be planted over the area. Some of us braid daffodil leaves, but others believe that braids draw attention to the deteriorating foliage.

Those of us who still dig and store and perhaps chill marginal bulbs, must wait for complete dormancy.

Pull Weeds Before They Seed

60323thumbSpring brings out the best and the worst in the garden. While warm season annuals and vegetables are getting established, so are a variety of weeds. Just like other annuals and perennials, they respond to the changing weather. Cool weather and moisture stratified their seed through winter. Warming moist soil prompts germination. Warm and sunny spring weather promts rapid growth.

There are all sorts of weeds. A few are big trees like bluegum eucalyptus and shamel ash. Some are substantial shrubbery, like privet and cotoneaster. Pampas grass and giant reed are big grassy perennials. The most familiar and prolific weeds are annuals or small perennials, like foxtail, burrclover, purslane, bindweed, sowthistle, pimpernel, spurge, crabgrass and Bermudagrass.

It is best to pull weeds as soon as they are big enough to grab onto. It will take more effort to pull them as they disperse their roots, and as the soil gets drier through spring. Unwanted shrubbery and tree weeds should be pulled like any other weed because they are likely to regenerate from roots if merely cut down. Once they recover and grow more, they will be much more difficult to pull.

Many small grassy weeds can be cut down low with a weed whacker, instead of pulled out completely. In some situations, low cut or mown weeds are better than bare soil. Some types of weeds will neither bloom nor disperse seed if mown. However, many types adapt to mowing by merely blooming and seeding lower. Dandelion and foxtail are notorious for their defiance to mowing.

Weeds are very efficient and creative with the dispersion of their seed. It is impossible to prevent seeds from coming into the garden from the outside. Yet, it is still best to inhibit the production and dispersion of seed from within the garden. Spurge and oxalis bloom and disperse seed in secret before they seem to be mature enough to bloom. Other weeds have taller or more prominent blooms that can be cut down before producing seed, even if the weeds are not actually removed completely.

Crop Rotation Improves Vegetable Production

90327thumbA south or west facing fence is a perfect place to grow pole beans. Twine can be strung in a zig-zag pattern between single rows of partly protruding nails along the top and bottom. The spacing of the nails should match that of the pole bean plants. Bean seed sown at the base of the fence germinate and grow quickly. Vines are happy to cling to the string and climb to the top of the fence.

Alas, it is temporary. Pole beans are annuals. They start to grow now, produce all summer, and then yellow and ultimately die by autumn, leaving the fence bare again. If the technique is repeated in the same spot with the same sort of pole beans the following spring and summer, the plants could be noticeably less vigorous. Repeating if for a third season could be downright disappointing.

It is best to grow beans in a different location every year if possible. After a few years, they can return to the same fence. Until then, tall plants, like caged tomatoes or corn, can be cycled through the area in front of the fence. Tomatoes and corn also perform better if not grown in the same spots for more than one season at a time. This process of cycling crops is known as ‘crop rotation’.

Soil borne pathogens proliferate along with the host plants that sustain them. Such pathogens may not be a noticeable problem in the first year while they get established. However, they are likely to be established and ready to infest the same sorts of host plants more aggressively in a subsequent season. Crop rotation of the host plants to cleaner locations annually interrupts this process.

In local soils, crop rotation is likely more important to compensate for nutrient depletion. Tomatoes are greedy with particular nutrients that other vegetable plants may not need in such quantities. The same applies to other vegetable plants. Tomatoes planted where other tomatoes grew last year may notice a lack of the nutrients that they crave the most of. However, zucchini may not miss what the tomatoes of last year took. Conversely, tomatoes may not notice what may be lacking where zucchini or other vegetables grew last year.

Trees Need Clearance From Utilities

30320thumbPalm trunks grow in only one direction; upward, toward sunlight and away from gravity. Each trunk is equipped with only a single terminal bud. If that bud encounters an obstacle, it can not be pruned around it. Palm trunks that get get too close to high voltage cables, or that might sway too close with a breeze, must therefore be removed to maintain minimal clearance from the cables.

Queen palms are notorious for getting planted under high voltage cables because they are so often impulse purchases that get planted without much planning. They are popularly planted along rear fences, exactly where high voltage cables are often located. Mexican fan palms often grow along rear fences as well because that is where birds and rodents are likely to drop the seeds.

Trees with single central leaders, like redwoods, spruces and certain pines, will be disfigured if their main trunks need to be topped for clearance from cables. Removal of such trees is often more practical than this sort of disfigurement. More extensively branched trees like sycamores, ashes, oaks and elms, are more adaptable to clearance pruning if it is not too severely disfiguring.

It is much simpler to not plant trees that get too large under high voltage cables. Elsewhere in the garden, where there is enough lateral (side) clearance, vertical clearance is not such a problem for larger trees. Small trees like redbud, purple leaf plum, photinia and various pittosporums, either do not get tall enough to reach upper cables, or will require only minimal pruning for clearance.

Below high voltage cables, the lower cables are for lower voltage, telephone and television. ‘House-drops’ are the cables that extend from utility poles to houses and other buildings. Although clearance is not so important for these lower risk cables, limbs that lean on them and blow around in wind can be abrasive. Sagging limbs can cause utility cables to sag more than they should.

Unfortunately, those who prune trees for utility clearance are efficient, but rarely arboriculturally correct.

Summer Vegetables Replace Winter Vegetables

90320thumbEvery year at about this time, there is the same concern that it is too early to put summer or warm season vegetables into the garden. When the time comes, replacing warm season vegetables with winter or cool season vegetables will also seem to be too early. Nonetheless, it is best to start the transition early so the garden will be ready for production as the weather warms into spring.

Broccoli, cauliflower and cabbage that are in the garden now should have time to finish before warmer weather makes them bitter. If the warm season vegetable plants that will be planted in their place are adaptable to it, and if the spacing is correct, they can be planted in amongst the cool season vegetables so that they will be ready to go when the the outgoing vegetables get harvested.

Unlike most of the cool season vegetables, which are truly ‘vegetative’ vegetables, most of the warm season vegetables are actually fruits, which is why they start to develop in spring, and mature through summer. Tomato, pepper, cucumber, eggplant, corn, bean and both summer and winter squash are the most popular here. Most produce from spring to autumn. Some produce only once.

Corn and other vegetable plants that produce only once can be planted in phases every two weeks or so to prolong production. By the time one phase finishes, the next should be starting. Corn is more efficiently pollinated, and therefore more productive, if grown in square blocks rather than in narrow rows. Corn and many warm season vegetables should be grown from seed sown directly.

However, tomato, pepper, eggplant and maybe zucchini and other squash can be planted as small plants from cell packs, because only a few of each type are needed. A cell pack of six or eight cost about the same as a packet of seed, but all the seed in the packet are not really necessary. Besides, the small plants are less likely to be eaten by snails than newly germinating seedlings.

Motion As A Landscape Element

60120+Landscapes appeal to our senses. The colors and textures of blooms and foliage are visually appealing. Floral fragrance and foliar aroma appeal to the sense of smell. Fruits and vegetables can provide flavor. Wind chimes, fountains and birds visiting bird feeders might add a bit of delightful sound and motion. Yet, the motion of certain plants in the breeze is rarely considered.

Weeping willow is famous for the way it blows softly in even a slight breeze. Unfortunately, it is also famous for thirsty roots, structural deficiency, and getting too big too fast. Mayten can do the same on a smaller scale, and in drier situations. California pepper is somewhere in between, since it can eventually get too big, and might have structural problems, but takes a while to do so.

Some of the various eucalypti have softly pendulous stems as well. Lemon gum and red ironbark are two of the better known specie that know how to blow in a breeze. Silver dollar gum is nice too, even though it is not as pendulous or as dynamic in the wind. Eucalypti that get too big for home gardens can be seen blowing in the wind in larger landscapes, such as parks or on freeways.

Two of the best trees for motion in the wind are not as popular as they used to be. European white birch that was so popular in the 1970s has become considerably less common that the less pendulous (but brighter white) Himalayan birch. The elegant and formerly popular Chinese elm has been replaced by modern ‘improved’ cultivars with stiffer stems, like the Drake Chinese elm.

Almost all bamboos, most big clumping grasses, and many palms are ideal for taking advantage of breezes. Mexican weeping bamboo really is comparable to weeping willow, but on a much smaller scale. Taller bamboos can catch a breeze on top even if lower foliage is sheltered. Pampas grass, although certainly not for every garden, has both dynamic foliage and dynamic blooms.

Of course, plants that move in a breeze can only do so with a breeze. They can not do much if sheltered by larger trees or buildings.P81222++++

Pruning Late Might Be Justified

90313thumbThere may not be exceptions to every rule, but there are a few exceptions to the rule that winter is the best time for pruning. It is generally true that most plants are the most dormant through the coolest part of winter. It is also true that while they are the most dormant, most plants are less sensitive to pruning, as well as other horticultural techniques that interfere with their normal function.

However, certain ‘special’ plants get pruned later, either because it is healthier for them, or just because they are allowed to do what they do best in spring before getting deprived of some of what they need to do it with. Some get pruned rather soon after coming out of winter dormancy. Some should probably wait for their new spring growth to mature a bit. It is not as confusing as it sounds.

Evergreen plants that drop much of their older foliage through winter should probably be pruned late in winter or early in spring, essentially at the last minute, just before new foliage develops. If shorn early and deprived of outer foliage that should survive through winter, photinia looks scraggly as it continues to lose much of what had been inner foliage until new foliage develops in spring.

Red twig dogwood and some types of willows that are coppiced or pollarded to maximize production of their colorful twigs should be allowed to show off their colorful bark for as long as possible. Like photinia, they too can be pruned at the last minute, just before vascular activity resumes. However, red twig Japanese maple really should be pruned in winter so it does not bleed afterward.

Flowering cherry, plum, peach, crabapple and quince are grown for prolific but sterile bloom which is diminished by winter pruning. If they need it, they can instead be pruned after bloom, but before too much foliage develops, or after such foliage matures in late spring or early summer. They do not need to be pruned nearly as aggressively as fruiting trees that would otherwise produce too much burdensome fruit. Some may only need to have dead stems pruned out.

Nomenclature Is The Name Game

60302thumbNomenclature is a standardized technology of naming. It dictates the universal ‘botanical’ names of all plants, so that everyone everywhere can communicate more efficiently about horticulture. Botanical names might seem confusing, and maybe even unflattering, but they eliminate the confusion associated with regional common names that are as variable as languages and cultures.

For example, the white pine from Northern California is not the same as the white pine from Maine, even though they both have the same common name. However, Pinus monticola, the white pine from Northern California, is the same everywhere, even if grown in Maine. This particular botanical name is only for this particular white pine, so eliminates confusion with other white pines.

Botanical names are also known as ‘Latin’ names because they are (obviously) Latin. The first name is the more general part of the name, so is known as the ‘genus’ (or ‘genera’ in plural). The second name is the more specific part of the name, so is known as the ‘species’ (or ‘specie’ in plural). The genus name should be capitalized; but the species name is not. Both are italicized.

Acer is the genus of all maples. Salix is the genus of all willows. These names identify particular genera, but are no more specific alone. Acer rubrum more specifically identifies a popular North American maple that is known locally as red maple. Salix babylonica specifically identifies a common willow known locally as weeping willow. This is almost as specific as nomenclature gets.

A few specie have varieties or cultivars (cultivated varieties) which are variants of the basic species. Variety or cultivar names are added after specie names. They are capitalized, unitalicized and semi-quoted. For example, Acer rubrum ‘October Glory’ is the October Glory red maple. Olea europaea ‘Little Ollie’ is a fruitless, dense and short cultivar of the familiar European olive tree.

Nomenclature of plants is similar to nomenclature of cars. Buick, Chrysler and Mercury are genera of cars. Electra, Imperial and Grand Marquis are specie of Buick, Chrysler and Mercury, respectively. ‘Limited’, ‘Custom’ and ‘Brougham’ are their cultivars. There are of course many more plants with bigger and stranger names, but the system for identification works the same way.

Weeds Obviously Grow Like Weeds

90306thumbNot many of our favorite plants grow like weeds. We must help most of them along, and give them what they want. A few might naturalize and perform well on their own, but if they do too well and become aggressive or invasive, they too become known as weeds. Although we might prefer some of our favorites to be easier to grow, we are probably fortunate that more do not do too well.

Conversely, not many weeds are appealing plants when they invade our gardens. They might not be so disdainful if they provided fruit, vegetables or flowers, or were less aggressive with other plants. Instead, the conquer and occupy useful space, consume resources, and then toss their seed for the next invading generation. Their aggressive invasiveness is what makes them weeds.

There is no easy definition of ‘weed’. We know them only as unwanted plants, or plants where they are not wanted. Most are exotic (nonnative) plants that were once imported at a time when they were actually desirable. Some were vegetable or flowering plants grown in home gardens. Some were forage crops. Blue gum eucalyptus was imported for wood pulp. A few weeds are native.

Weeds become weeds because they have distinct advantages. Most get an early start at the end of winter, while other plants are still dormant. Then, many weeds bloom and toss seed for the next generation earlier than other plants. Many lack the pathogens of their homelands. Weeds generally survive on less resources, or complete their life cycles before resources are exhausted.

Most weeds are annuals. Many are perennials, Some are shrubby or vining. A few are trees. One commonality is that they should be pulled as soon as they are big enough to get a grip on. They are easier to pull while the soil is moist from winter rain, and before they have dispersed their roots much. Some of the short term annuals are pretty quick and sneaky about dispersing seed too!

Weeds that are woody shrubs, vines or trees need to get pulled like the rest. If merely cut to grade, they will likely regenerate from their stumps, and need to be dug later.