The other day in the hardware store I overheard someone ask the clerk for some rose food. My eyebrows went up as I thought to m’self, “Are they kidding, thinking that roses need their own special food? Next, I’ll hear about plants that prefer vegetarian or kosher food, perhaps fish emulsion on Fridays?”
All this food science when it comes to plants may boost fertilizer sales, but it hardly bothers plants either way. Plants take up the bulk of their nutrients as ions (charged atoms or groups of atoms) that are dissolved in water in the soil. Rock particles, as well as humus and organic fertilizers, decompose to release nutrient ions slowly into the soil solution. Chemical fertilizers are already in ionic form, so when you sprinkle a handful on the soil, they dissolve as soon as they contact water.
A Well-Rounded, Wholesome Diet
What’s so special about rose food for roses? Nothing. All plants need healthy doses of nitrogen, phosphorus, and potassium, and lesser amounts of other nutrient elements. But unless a soil is an infertile sand where neither crop rotation nor some weed growth is allowed to balance soil nutrients, specific foods don’t usually have to be tailored for specific plants.
My garden grows pretty well, and I feed all my plants the same diet: An annually replenished mulch of wood chips, leaves, or compost, and, if extra nitrogen is needed, an annual sprinkling of soybean meal. Theoretically and in practice, an inch depth of compost alone provides sufficient nourishment for the plants. That inch depth of compost is the only thing my vegetable beds get each year, and it nourishes closely planted cabbages, tomatoes, lettuces, and other plants from the first breath of spring until cold weather barrels in to shut down production.
Garden plants that are pressed into sustained production (nonstop flowering of those rose bushes, for example) or vegetables best plumped up with extra-succulence, like some leafy vegetables, might need an extra push with additional nitrogen. Or not.
Soybean meal, available in garden centers as well as anywhere selling animal feeds, is insurance in the form of a high nitrogen, organic fertilizer. Cottonseed meal, hoof and horn meal, alfalfa meal, or blood meal would serve as well. Soil microorganisms decompose the proteins in any of these fertilizers in a series of steps to produce amino acids, then ammonium ions, then nitrate ions. The latter two ions are the forms of nitrogen most utilized by plants.
I grew Brussels sprouts unsuccessfully for many years, with sprouts hardly bigger than marbles lining up along the spindly stalks. So last year, I sprinkled some soybean meal (2 pounds per hundred square feet) on the ground before laying down the compost. Success! The plants grew into sturdy, five-foot-high stalks along which were lined up almost golfball-sized sprouts.
Flowers and mature trees and bushes get nothing more than arborists’ wood chips, leaves, hay, straw, or wood shavings here. Even these low nitrogen mulches eventually release nitrogen as their lower layers break down in the soil.
But Still . . .
You might point out that, still, there are some plants that need a specialty plant food: “acid plant food” for azaleas and rhododendrons, for example. You’ve got a point; these plants do have special needs. But my universal pabulum of mulch and soybean meal also suffices for them.
The special requirement of these plants is an acid soil. If a soil is not naturally acidic, the soil doesn’t need an “acid plant food,” it needs to be made acidic. The way to make a soil acidic is with sulfur, a naturally mined mineral. The amount needed depends on the existing soil acidity (determined with a quick soil test), the desired soil acidity (a pH of about 5 for acid-loving plants), and whether the soil is sandy or clayey. A sandy soil needs about 3⁄4# per 100 sq. ft. for each pH unit change; clay soils need about two-and-a-half times that amount. The sulfur to use is “pelletized” because it’s less dusty to work with. And, obviously, any compost for these plants should have had no added limestone.
What about the special nitrogen requirement of these plants? Commercial “acid plant food” supplies acid-loving plants with their preferred form of nitrogen, which is ammonium ion. Let’s see what happens to my soybean meal in an acid soil. A few paragraphs earlier, I wrote that though an orchestrated series of steps, various soil microorganisms gobble up proteins in soybean meal or other organic fertilizers, breaking them down to amino acids, ammonium ions, and then nitrate ions. In acidic soils, microorganisms that do that last job are absent. Breakdown stops at ammonium ion — just what those plants like best.
Green Thumb Not Needed
Anybody out there now sprinkling seeds into mini-furrows in seed flats, flowerpots, or repurposed yogurt cups? How many of us are then disappointed when, a few days later, there’s no sign of green sprouts poking up through the brown soil? Or not enough of them.
A green thumb isn’t a prerequisite for growing seedlings indoors to give plants a head start for earlier ripening of tomatoes and peppers or earlier blooms of zinnias or marigolds. Backing up every seed is 350 million years of trial and error; seeds have evolved to sprout. So why, sometimes, don’t they, and how do to right any wrongs?
Good Seeds and Good (Potting) Soil a Must
Seeds are living, breathing creatures, and don’t live forever. How long a seed remains viable depends on the kind of seed. Longevity of vegetable seeds under good storage conditions goes from just a year for onion, parsnip, and parsley seed to more than four years for seeds of cucumber, lettuce, and cabbage and its kin. Most annual flower seeds are good for one to three years, most perennials two to four years.
But don’t take any reports of seed longevities too much at face value. Storage conditions play an important role, with the best conditions being cold and dry. I store my seeds in an airtight tub along with packets of silica gel that I weigh and refresh, if needed, in a microwave oven. The tub winters in my unheated garage and summers in my cool basement, or freezer.
Next, turn to the soil or, more correctly, the potting mix or potting soil. Don’t sow seeds in garden soil, even good garden soil. Garden soil becomes too sodden in the confines of a container. Purchase or make your own mix (both of which I wrote about my March 15, 2022 blog post).
Gather up some bona fide or makeshift containers, and you’re ready to plant. Any container that’s a couple of inches deep with drainage hole in its bottom is suitable. Fill it with the potting mix and gently firm it.
A guideline that I don’t follow rigorously is to plant seeds at a depth approximately four times their thickness. A lighter, airier mix warrants deeper planting or seeds will dry out too quickly. Still, bigger seeds do warrant deeper planting than smaller seeds. With really tiny seeds, like foxglove or portulaca, I just sprinkle them on the surface, perhaps with a smidgen of potting mix for a very light cover. Tiny seeds have tiny energy reserves, and if planted too deep, they burn up all their energy before peering aboveground to drink in energy-giving light. No matter the depth, right after sowing I firm the seedbed for good contact between seeds and mix.
And then I water. I could water from above with a gentle “rain” from the fine rose of my watering can or hose wand, but prefer to minimize washing around the potting mix and seeds, especially small seeds, by watering from below. I set the seed flat or container in a pan with an inch or so of water and let it sit for a few hours. By then the potting mix is saturated with water; lifting the container out of the water and then tipping it at an angle drains excess (gravitational water) from the mix. A pane of glass over the top of the container prevents evaporation to lock in moisture.
All the seeds now need to coax them out of the slumber is warmth. Each kind of seed has a minimum, a maximum, and an optimum temperature for germination. Unfortunately, it’s not the same for all seeds. Between 70 and 80 degrees Fahrenheit (21-27° C.) strikes a nice balance for all of them.
Armed with a thermometer, check out warm spots around your home: perhaps it’s a warm room, the top of a refrigerator, an insulated container along with a periodically refreshed hot water bottle, or near a furnace. Electric seed heating mats are available, some raising the temperature 10° F above ambient, more expensive ones raising the temperature to whatever amount you dial in.
I made my own germination chamber from a styrofoam cooler along the bottom of which I wired two sockets each with a 15 watt lightbulb. Above the bulbs sits a rack for the seed flats. The bulbs are wired into a thermostat on which I can dial the desired temperature set, always, in my case, set to 80° F.
One Final Ingredient and You’re Good to Grow
That’s it, except for one final ingredient: patience. Even with ideal conditions, seeds vary in how long they take to germinate.
I check the containers every day and as soon as sprouts appear, I uncover and whisk the container to bright light. From then on, cooler temperatures — about 10° F. less than germination temperatures — and bright light are ideal.
Shrubs are Shrubby
A shrub is a shrubby, woody plant. (Now, that’s profound.) Numerous stems originating at or near ground level are what make a plant shrubby. Usually, no one stem ever gets the upper hand over other stems. For most shrubs, you need to get out there with your pruners to snip and lop every year.
How to prune a shrub depends on when it flowers and on what age stems provide the most ornamental effect. Does the shrub flower early in the spring, or later in the summer? Does it flower on old stems, on those that grew last year, or on new shoots?
And one more thing before we dive in: Here, I’m writing about pruning shrubs growing informally. Let’s shelve pruning hedges and, because they vary so much in their pruning needs, roses for another time.
Deciduous shrubs can be put into one of four categories according to the age of stems that flower or otherwise look their best. Here are some bare-bone guidelines for each of these categories. In my book, The Pruning Book, from which this is excerpted, I offer more detailed guidance with extensive lists of plants in each category (and, of course, details on pruning hedges, roses, and just about any other plant or pruning technique you can think of. Really.)
Old Looks Best
Deciduous shrubs whose old wood flowers or looks best. Included within this category are shrubs — witch hazel, rose-of-sharon, tee peony are examples — that naturally build up a permanent framework of branches. Rarely do they send up new suckers at or near ground level. These shrubs flower directly on older wood, or from shoots that grow from older wood. Grouping plants always entails a certain degree of arbitrariness, and because of their disinclination to sucker, a few plants in this category could also be considered “trees,” especially if deliberately trained to one or a few trunks..
These shrubs are the easiest shrubs to prune: mostly, just don’t!
Some Annual Pruning Helps
Deciduous shrubs that flower best on one-year-old wood. Because they all flower only on wood that grew the previous season, annual pruning is needed to stimulate new growth, each year, for the following year’s flowers.
Renewal prune each year, removing the very oldest stems to make way for younger, floriferous stems to step in and replace older stems. Cutting a few stems low in the shrubs is also less work than shearing, and creates a more graceful, fountain-like growth habit, and keeps the plant low, neat, and abundantly flowering.
Prune those shrubs that flower early in the season right after their blossoms fade. But now, or just before growth begins, is the time to prune those shrubs that flower from summer onward. Pruning early-flowering shrubs right after they bloom allows you to enjoy their blossoms, but still leaves enough time for shoots to grow and ripen wood sufficiently for next season’s blooms.
The one-year-old shoots on which flowers are borne may grow mainly from older stems up in the shrub, or else mostly from ground level. The location of these flowering shoots determines pruning technique, so I have subdivided this category into two groups, grouped plants accordingly, and follow with instructions for each.
Shrubs such as lilac, forsythia, and mock orange flower best on one-year-old wood originating from older wood up in the plant.
Peer in at the base of the mature plant and you’ll notice wood of various ages growing up from ground level. Begin pruning by cutting away near ground level, some of the very oldest stems. Those oldest stems are also the tallest ones, so these first cuts quickly lower the plant.
Each year also remove at ground level a portion of the youngest stems so they don’t crowd with age.
Abelia and kerria are among those shrubs that flower best on one-year-old wood originating at ground level; they need more drastic pruning. Every year cut away all wood more than one-year-old, either right to ground level or else to a vigorous branch originating low on the plant. You can tell the age of a stem by its thickness and, with many plants, by the color or texture of the bark.
Blossoms on New, Growing Stems
Deciduous shrubs whose current growth flowers or looks best: Here we have shrubs valued only for their new growth. And yes, in some cases we value the plant for the young stems themselves.
This group of shrubs, which includes red-osier dogwood (whose young, red stems “ignite” with winter cold), butterfly bush, New Jersey tea, and Hills-of-Snow hydrangea, is very easy to prune: simply lop the whole plant down to the ground just as buds are swelling.
Time for Renovation?
You perhaps have inherited, with your property, a neglected, old shrub offering you a tangled mass of stems, an awkward posture, and few flowers. Can this shrub be brought back to its former glory? Probably.
You have two options in renovating this shrub. The first is the drastic one: you merely lop the whole plant to within one foot of the ground just before growth begins for the season. The plant won’t be pretty for a few years but after that you’re on your way to a “new,” shrub, full of blossoms and with a graceful growth habit, a whole new plant from the ground up.
A second option is gradual renovation, removing a couple of the oldest stems each year over a period of four or five years. Although this takes more time, the plant will look decent throughout the recovery period.
Rather than renovation, you might instead consider capitalizing on your overgrown shrub’s age and venerability by transforming the plant into a picturesque small tree. Not all shrubs make this transition gracefully; devil’s walkingstick, hawthorn, and hazelnut are among those that do.
Select as trunks two or three of the oldest stems having pleasant form and growing from ground level to as high as the proposed crown of your tree-to-be. Remove all other growth from ground level to the proposed crown.
Even easier is to let the deer prune for you, in which case the bottom of the crown will be as high as the deer care to reach.