| FERTILIZATION CHART |
|---|
FIRST - DO A SOIL TEST
Such a test, administered by you or by a lab, will identify:
which nutrients your soil has in abundance
which nutrients your soil is deficient in
NOTE
Fertilization recommendations below assume you have soil of reasonable or average fertility. |
| BOTANICAL | COMMON | Y/N |
HOW/WHEN |
| Achillea | Yarrow | yes |
carefully - avoid excessive nitrogen |
| Aconitum | Monkshood,
Wolfbane | yes |
annually |
Actaea
formerly
Cimicifuga |
Black Snakeroot,
Black Cohosh | yes | regularly |
| Ajuga | Bugleweed,
Carpet Bugle | yes |
balanced solution (granular forms can burn) |
| Alcea | Hollyhock |
yes | top dress in spring with compost, manure or a balanced organic fertilizer |
| Allium | Ornamental Onion | yes |
mix fertilizer or bone meal into soil before planting OR
apply when new growth appears |
| A. schoenoprasum | Chives,
Common Chives | yes | early, then monthly during growing season |
| Amsonia | Blue Star | yes | regularly |
| Anchusa | Bugloss,
Italian Bugloss,
Ox-Tongue,
Alkanet | yes | after flowering for second flush |
| Anthemis | Golden Marguerite,
Yellow Chamomile |
yes | lightly to avoid over-fertilizing |
| Aquilegia | Columbine | yes |
regular light feedings 20-20-20 half-strength;
in spring, then monthly with Iron Plus 24-8-16;
aged compost |
| Armeria | Thrift,
Sea Pink | yes |
lightly and only in the poorest soil |
| Artemisia | Wormwood,
Mugwort | yes |
lightly; handful soft rock phosphate for root growth;
avoid over-fertilizing |
| Aruncus | Goatsbeard | yes |
regularly during growing season, slow-release fertilizer annually |
| Asclepias | Butterfly Weed | no | not necessary, little fertilizer is required |
| Aster | Aster | no | sparingly, if at all |
| A. dumosus | Bushy Aster,
Long-Stalked Aster,
Rice-Button Aster | yes | complete (mild) fertilizer |
| Astilbe * | Astilbe,
Garden Spirea,
False Spirea |
YES | a heavy feeder that depletes soil quickly and reduces flowering:
at planting: use balanced fertilizer
when dividing or transplanting: slow-release 0-20-20
in spring:
sprinkle fast-acting 5-10-5 and repeat later OR
handful of slow-release around clump OR
balanced organic form |
| Aubrieta | Rock Cress | yes |
monthly with water soluable 24-8-16 |
| Aurinia | Basket-of-Gold,
Perennial Alyssum,
Basket of Gold | yes | only lightly to avoid over-fertilization |
| Azalea | Azalea | yes | early spring or fall |
PRIMARY CHEMICAL FERTILIZER ELEMENTS
The Primary Elements (N, P & K) in a chemical fertilizer produce specific results:
Nitrogen (N) stimulates growth rate & greens up foliage so it can process nutrients more efficiently
Phosphorus (P) stimulates root growth
Potassium (K) stimulates flowering and fruiting |
| Baptisia | False Indigo | no |
little, if any as it "fixes" its own nitrogen |
| Belamcanda chinensis | Blackberry Lily | yes | monthly during growing season |
| Bergenia | Pig Squeak,
Elephant Ears |
yes | regularly |
|
Boltonia | Boltonia,
Bolton's Aster | no |
regular fertilization will cause floppiness |
| Buddleia | Butterfly Bush | yes |
lightly, in spring when new shoots appear, then regularly during bloom season;
slow-release formulas (Osmocote) for early shoot & leaf development without delaying flower formation;
over-fertilizing causes excess leaf growth & few flowers |
| BULBS
Like perennials, different bulbs have varying fertilization requirements. Check the individual recommendations for Alliums, Dahlias, Fritillaria, Gladiolus, Hyacinths, bulbous Iris forms, Lilies, Narcissus, Polyanthes and Tulips in the alphabetical list on this page.
| Buxus | Box,
Boxwood | yes |
spring or very late fall when dormant |
ORGANIC FERTILIZATION
Chemical fertilizers can give individual plants a boost but are no substitute for building up soil quality with organic matter, which will eventually decrease the need for chemical nutrients.
Organics include such materials as dried blood, fish emulsion, feather meal, rock phosphate, bone meal, sunflower seed hull ash and seaweed. They contain a smaller percentage of nitrogen, phosphorus and potassium than chemical (synthetic) fertilizers. |
| Chrysanthemum | Chrysanthemum
Mum | |
|
C. coccineum
now -
Tanacetum coccineum |
Pyrethrum | | |
C. x morifolium
now -
Dendranthema x. grandiflorum |
Garden Mum
Cushion Mum | yes |
at time of planting: fertilize well
planted spring or summer: use all-purpose granular formula
spring transplants: water with liquid balanced (20-20-20) fertilizer
monthly: with liquid fertilizer through mid-late July for vigour
late July: stop all fertilization |
C. parthenium
now -
Tanacetum parthenium |
Feverfew | | |
C. x superbum
now -
Leucanthemum x superbum |
Shasta Daisy | yes | occasionally |
C. x rubellum
now -
Dendranthema zawadskii |
Korean Chrysanthemum | | |
| Clematis | Clematis | yes |
early spring: begin a feeding program of:
a compost mulch and
a handful of bone meal mixed into the soil
during active growth:
general purpose liquid fertilizer every 2 weeks OR
granular slow-release fertilizer
after buds form: discontinue fertilizing until flowering is finished
mid-August: stop all fertilization
Note: always use a low nitrogen formulation |
COMPLETE VS INCOMPLETE FERTILIZERS
A "complete" fertilizer contains all three main elements - Nitrogen, Phosphorus and Potassium.
An "incomplete" fertilizer may provide just one or two nutrients i.e. blood meal, bone meal. |
| Dahlia | Dahlia | yes |
liquid formula occasionally early July - early September |
| Delphinium * |
Delphinium | YES | this is a heavy feeder
seedlings: diluted 10-10-10 liquid formula once weekly;
plants: in spring when stems are 1" high with a balanced 12-12-12 granular formula; OR
5-10-5 at planting & 5-10-10 in spring and after bloom;
generally: fertilize regularly;
5-10-10 in early spring and again later during season with complete formula, especially after cutting back first flush, to encourage second bloom |
| Dianthus |
Pink | no | generally not necessary |
| D. x allwoodii |
Modern Pink,
Allwood's Pink | yes | in spring |
| D. arenarius |
Sand Pink | yes | in spring |
D. caesius,
D.
gratianopolitanus | Cheddar Pink | yes |
in spring |
| D. deltoides | Maiden Pink | yes |
in spring |
| D. knappii | Yellow Pink | yes |
in spring |
| Dicentra |
Bleeding Heart | yes |
in spring, then regularly therafter; use an organic mulch |
Dictamnus,
Fraxinella (old name) |
Gasplant,
Dittany,
"true" Burning Bush | yes |
lightly with an occasional sprinkling during growing season |
| Digitalis |
Foxglove | yes | early |
EVERYTHING THE SAME METHOD
Don't have time to compost? Tired of researching which plants need which fertilizers? You may want to use a method that lets you fertilize everthing in your gardens the same way and with the same formulation. If so, try this light fertilization program to give a continuous supply of nutrients for healthy plants:
use 5-10-5 fertilizer
place in small rings around each plant in March
repeat twice at 6-week intervals
apply again to late-blooming plants in late summer
always water after applying fertilizer to remove fertilizer from foliage and prevent burn
|
| Echinacea * |
Coneflower | YES | heavy feeder;
spring: balanced formula, lightly
summer: regularly |
| Eryngium | Sea Holly,
Eryngo |
no | prefers low fertility |
| Euphorbia | Spurge |
yes | add a light application of organic fertilizer to the planting hole |
| E. cyparissias | Cypress Spurge | no |
pefers low fertility |
CHEMICAL FERTILIZER CHOICES
Once you've decided to fertilize your plants chemically, you need to become familiar with the fertilizer types available. They include:
dry granules
solid pellets, tablets or spikes
liquids or soluble powders |
| Filipendula |
Meadowsweet | yes | regularly |
| Fritillaria imperialis |
Crown Imperial Fritillary | yes |
prepare soil several inches below where bulbs will rest, adding sand for best drainage and to prevent rot; mulch with compost or feed with well-rotted manure in spring |
| Fritillaria meleagris | Checkered Lily, Guinea-Hen Flower, Snake's Head Fritillary | yes | see Fritillaria imperialis above |
HOW TO MAKE YOUR CHOICE - I
GRANULAR FERTILIZER
the least expensive per pound of nutrient
for both lawns & gardens (new or established)
available in 2 distinct forms
slow-release form
more expensive initially but cost-effective in the long run
requires fewer applications
coating reduces speed with which the nutrients become available
supplies a steady supply of nutrients over an extended time
minimizes problems related to leaching of nutrients or overdose of some elements, particularly nitrogen
quick-release form
makes most nutrients available just after application
lasts one season or less |
| Gaillardia |
Blanket Flower | no | not necessary |
| Geranium |
Hardy Geranium
Perennial Geranium
Cranesbill |
yes | top-dress in spring with compost, well-rotten manure or a balanced organic fertilizer |
| Gladiolus | Gladiolus | yes |
planting: bonemeal (1 cup per 3 ft of row);
after flowers form: balanced formula, general purpose or liquid type, i.e. RX-15, Hyponex, Instant Vigoro, etc. |
HOW TO MAKE YOUR CHOICE - II
SOLID, PELLETIZED FERTILIZERS
compressed particles pre-formed into tiny, bead-like particles, tablets or spikes
more costly per pound of nutrient than granular fertilizers
many are slow-release which offsets cost
place beneath soil surface; esp. useful for container plants, trees or individual plants
more convenient to apply than granular fertizilers |
| Hedera | Ivy | yes |
dust base in spring with an all-purpose formula |
| Helianthemum |
Rock Rose | no | sparingly, if at all |
| Helianthus |
Perennial Sunflower | no | seldom or occasionally, if at all |
| Heliopsis | False Sunflower,
Oxeye,
Sunflower Heliopsis | yes | regularly |
| Hemerocallis |
Daylily | yes |
spring only: handful 10-10-10 scattered around each plant and lightly scratched in; OR
spring, summer and fall: 12-12-12 lightly once each season |
| H. 'Stella d'Oro' | 'Stella d'Oro' Daylily |
yes | lightly and only in the poorest of soils |
| Heuchera |
Coral Bells,
Alumroot | yes | balanced formula |
| Hibiscus | Hibiscus | yes | regularly |
| H. syriacus | Rose of Sharon,
Shrub Althea |
no | not necessary, very lightly, if at all;
do not overfertilize;
OR
spring to fall: use low phosphorus formula i.e. 10–4-12 regularly |
| Hosta | Hosta,
Funkia | yes |
seedlings: dilute solution liquid formula once monthly until planting out |
| Hyacinthus | Hyacinth | yes |
granular formula just as blossoms fade |
| Hydrangea | Hydrangea | yes |
in spring: commercial formula or rotted manure/compost |
| Hypericum | St. John's Wort |
no | only lightly, if at all; do not overfertilize |
HOW TO MAKE YOUR CHOICE - III
LIQUID FERTILIZERS
concentrates or powders to be mixed with water and appled directly to soil or sprayed onto foliage
some contain only nitrogen, phosphorus and potassium
others are a source of a single trace element
an excellent source of readily available nutrients
useful for quickly correcting deficiency symptoms and for fertilizing soilless mixes
can be used for the same purposes as granular or pelletized fertilizers, but tend to be more costly and require more frequent application |
| Ilex | Holly | yes |
late winter: at 1 lb. 10-5-5 per inch of trunk diameter, in circle 3 feet or larger around plants; slow-release formula is best
early summer: at 1/2 winter strength
late summer: with urea or other nitrogen-rich formula |
| Iris | Iris | yes |
composted cattle manure or Grow-Rich (5 lbs. per square yard) worked into loosened soil at planting; 4-8-12 in early spring |
| I. danfordiae | Danford's Iris - an early spring-blooming bulbous form |
yes | Bulb Booster in fall |
| I. x germanica |
Bearded Iris | yes |
slow-release, 3 weeks before planting; superphosphate in spring and bone meal in fall (both as side dressing) |
| I. sibirica | Siberian Iris | yes |
18-21-21 (to mitigate transplant shock) |
COMPOST - "BLACK GOLD"
Chemical fertilizers may be the simplest solution to boosting flower production but for long-term results nothing beats a regular application of compost to improve the soil itself. There are numerous methods suggested to produce compost, some more labour-intensive than others, and you must decide how much time and effort you are prepared to invest in the process. The two naturally-occurring ingredients most commonly used in composting and readily available to every home gardener are:
grass clippings
fallen leaves
How you build and maintain your compost pile will ultimately affect the length of time it takes to produce compost as well as the quality of the finished product itself.
|
| Juniperus | Juniper | yes |
at planting time: use Plant Start |
SIMPLE SOIL SCIENCE
Although there are many degrees between them, the basic soils are:
Sand: very large particles, with big spaces between them, allowing water to pass through too quickly
Loam: full of body, highly workable, nutrient-rich and appropriately moisture-retentive
Clay: very tiny particles, with almost no space between them, allowing water to pass through too slowly
For the best soil you can create, choose soil amendments that correct the deficiencies in each of the above. |
| Kerria | Japanese Kerria Shrub | no |
not necessary, only lightly and occasionally, if at all
too much will encourage rampant growth |
AMENDMENTS FOR SANDY SOIL
Although compost is one of the best soil amendments for sand, there are others that can help create the loam in which our plants will thrive. Such amendments for sand include:
loam
organic matter: manure, seaweed, peat moss, leaves, straw, plant refuse |
| Lamium | Spotted Dead Nettle | yes |
when planting: sprinkle 14-14-14 under roots |
| Lilium * | Lily |
YES | a heavy feeder;
low nitrogen, high phosphorus and potassium formula i.e. 5-18-32
when planting: add to hole
spring: use as a top-dressing
new beds: complete 4-8-12 mixed into new bed, then 3 times annually
at 1/2 c. per clump of 4-5 lilies:
first at 6"
second 1 month later
third another month later |
| Limonium | Sea Lavender |
yes | apply all-purpose fertilizer monthly |
| Linum |
Flax | no | |
| Lupinus | Lupine | yes |
spring & summer: handful of 5-10-5 sprinkled around plant
late June: side-dress with 20-20-20 |
| L. polyphyllus | Washington Lupine |
yes | bone meal spring and fall around plants |
AMENDMENTS FOR CLAY SOIL
Although compost is one of the best soil amendments for clay, there are others that can help create the loam in which our plants will thrive. Such amendments for clay include:
organic matter: wood ashes, rotted manure, peat moss
sand, esp. coarse or ungraded sand
ground limestone
gypsum |
| Monarda | Bee Balm | no |
rarely and only in the poorest soils; generally withhold to prevent rapid spread |
| M. Panorama Mix | Bee Balm | yes |
monthly: water soluble Iron Plus 24-8-16 |
| Myosotis | Forget-Me-Not |
YES | feed liberally |
THE GOAL
Whether your soil is light sand or heavy clay, or one of the many stages in between, the ultimate goal of using soil amendments is to create humus that will allow the soil to absorb an appropriate amount of water and make the nutrients in the soil more available to the plants growing in it. |
| Narcissus |
Daffodil, Jonquil | yes | never use manure
immediately after bloom: with 0-20-20 granular formula with 1 Tbsp. around each clump
when replanting: add 6" rough compost to bottom of planting hole & 4-5" of "prepared" soil consisting of 1/3 garden soil, sifted into wheelbarrow above 1/3 sifted compost and 1/3 vermiculite (best) or coarse builder's and fertilize again when green tips appear in spring (1 Tbsp. 5-10-5 granular around each clump; OR dig some dried manure into top 1-2" of soil); OR mix Bulb Booster when planting into 2" of soil under bulbs, then when shoots appear in spring add 9-9-6
Derek Fell recommends high phosphorus fertilizer twice annually:
in spring before bloom and
in fall after the first frost |
AMENDMENTS VS. MULCHES
It is important to know the difference between these terms, to determine how you should use various materials, usually organic, in your garden.
Amendment: material mixed into the soil
Mulch: material added on top of the soil |
| ORNAMENTAL GRASSES
By and large, Ornamental Grasses, as you will read below, do not require and may actually resent fertilization.
| Ornamental Grasses | all - including:
Arrhenatherum,
Calamagrostis,
Carex (a Sedge)
Chasmanthium,
Deschampsia,
Elymus,
Festuca,
Hakonechloa,
Helictotrichon,
Imperata,
Miscanthus,
Molinia,
Panicum,
Pennisetum,
Spartina |
NO | Rick Darke, a renowned grass expert in the United States and author of "The Color Encyclopedia of Ornamental Grasses" as well as "Timber Press Pocket Guide to Ornamental Grasses" states that ornamental grasses do not benefit from fertilization and may, in fact, be negatively affected by it.
So, unless you want to risk causing overly lush growth, floppiness, loss of shape and diminished effects of foliage variegation, don't even consider adding fertilizer of any sort to your grasses, or grass-like sedges.
|
AMENDMENTS
These are mixed into your soil to improve its quality.
Some, but definitely not all, amendments also make good mulches. An example is compost. Whether you mix it into your soil or spread it on top and let the earthworms do the work for you, compost is the perfect soil conditioner.
On the other hand, some amendments make terrible mulches. An example is peat moss. While this is a wonderful, moisture-retentive amendment, it should never be used as a mulch, on the soil surface, where it can form a dry, impenetrable barrier keeping water from entering the soil beneath. |
| Paeonia | Peony | yes |
spring: bone meal as leaves unfold
early summer: immediately after blooming
late summer: general fertilizer after bloom
Larkwhistle formula at planting time: mix 2/3 topsoil, 1/3 very old manure, 3-4 shovelsful peat moss, 1 of wood ashes and a few trowels of bone meal in planting hole
caution: avoid over-fertilization, esp. with nitrogen that can predispose plants to botrytis and other diseases |
| PERENNIALS
Different perennials have varying fertilization requirements. Check individual recommendations for each of the species in the alphabetical list on this page to be sure you are providing exactly what your plants require to provide their peak performance.
| Papaver | Poppy | no |
prefers only average fertility |
| Penstemon | Beard-Tongue | yes |
sparingly, when spring growth starts, with a complete organic fertilizer |
| Phlox paniculata | Garden Phlox | yes | early spring, then regularly thereafter
at planting: add compost or peat moss |
| Phlox subulata | Moss Phlox, Creeping Phlox | yes |
need constant supply of nutrients for strong, steady growth: always water plants thoroughly after both fertizer applications described below.
in early spring: just after stem tips show at soil surface sprinkle 9-12-12 timed-release fertilizer into soil around plants, then mulch the area
mid-summer: pull back mulch, sprinkle fertilizer onto soil around plants, then replace mulch |
| Polyanthes | | yes |
liquid formula every 2 weeks when in growth |
| Primula | Primrose | |
recommendations vary from source to source as well as from species to species |
| P. x polyanthus | Polyanthus Primrose | yes |
side-dress only occasionally |
| Pyrethrum - see: Tanacetum coccineum | Pyrethrum,
Painted Daisy | yes |
use general purpose fertilizer when preparing soil |
MULCHES
A mulch is applied on the surface of the soil for one or more purposes:
to hold in moisture
to prevent weed growth
to moderate soil temperature
to improve the appearance of the soil
If you do use any kind of mulch, there are a few things to remember.
keep it loose
keep it between 2-4" deep
keep it away from the crowns of the plants
For detailed information on various mulch materials follow the link to the
Flower Gardening Made Easy site. |
| Rhododendron | Rhododendron | yes |
early in season: with evergreen fertilizer; do not overfeed
caution: never fertilize after June 20
do not use aluminum sulphate to acidify soil |
| Rudbeckia |
Coneflower | no | not necessary |
WINTER MULCH
The purpose of applying a winter mulch is quite different than for summer mulches as described above.
Its purpose is definitely not, as some people think, to keep plants toasty warm during winter months.
A winter mulch is intended to KEEP THE SOIL FROZEN, in order to prevent the plant and its roots from heaving out of the soil during winter freeze and thaw cycles.
Do not apply a winter mulch too early. Wait until the ground is completely frozen so that it can do its job properly. |
| SHRUBS
While the list on this page is mostly comprised of Perennials, there are a few shrubs included. To date you will find either above or below the fertilizer requirements of Boxwood, Hibiscus, Holly, Japanese Kerria, Rhododendrons and Lilacs.
| Syringa | Lilac | yes |
at planting: spread roots of bare-root plants out fully
add 10-6-4 to backfill at 1/2 handful for 1 quart-sized plant AND
at 1-2 handsful for 1-gallon-sized plant; fill hole and water in
every two years: apply 10-6-4 formula as per instructions |
SOIL & pH LEVELS
Remember the soil test recommended at the top of this page? In addition to nutrient levels in your soil, this test will also reveal its pH level.
WHAT IS pH?
Simply put, pH is a measure of the hydrogen-ion concentration of the soil on a scale from 0 to 14. Soil acidity will register on the lower end of the scale, while soil alkalinity will register on the upper end of the scale. Neutral soil is the area between the two extremes.
WHY DO YOU NEED TO KNOW ITS LEVEL IN YOUR SOIL?
The pH level of soil will determine the Availability of Existing Nutrients to anything planted in it. |
Tanacetum coccineum
formerly Chrysanthemum coccineum |
Pyrethrum | yes | use general purpose fertilizer when preparing soil |
| Trillium |
Trillium,
Wake Robin | yes |
plant in late September when going dormant;
when planting: mix 1 Tbsp. each muriate of potash & superphosphate into soil at bottom of 3" deep planting hole, add 1/2" soil to keep tuber & roots from contacting fertilizer direct, position tuber horizontally on soil, water thoroughly, fill planting hole with mixture of leaf mold and soil, water again and mulch with shredded leaves or coarse compost
when shoots first appear AND right after flowers fade: apply solution of liquid fertilizer i.e. Peter's Blossom Booster 10-30-20 |
| Tulipa | Tulip | yes | never add manure
when planting: mix Bulb Booster in 2" of soil under bulb
spring and fall: with all-purpose formula or Bulb Booster
spring: 9-9-6 when shoots show through ground |
DEGREES OF ACIDITY & ALKALINITY
A large number of perennial plants grow perfectly well in soil in the slightly acidic, through neutral to slightly alkaline range. Nevertheless, you may run across the following terms and should know what they mean in reference to the plants you grow.
strongly acidic pH - 4.5 to 5.2
medium acidic pH - 5.3 - 6.4
slightly acidic pH - 6.5 - 6.9
neutral pH - 6.9 - 7.1
slightly alkaline pH - 7.1 - 7.5
medium alkaline pH - 7.6 - 8.2
strongly alkaline pH - 8.3 - 9
|
| Veronica | Veronica, Speedwell | no |
not necessary |
| Veronicastrum | Culver's-root, Bowman's-Root, Blackroot | yes | regularly |
| Vinca | Myrtle | yes |
water/feed with lawn fertilizer 3x per season |
| VINES
Even vines can differ in their fertilization needs. To date, you can find the following vines in the alphabetical list on this page in order to check their exact requirements: Clematis, Hedera (Ivy) and Wisteria
MODIFYING pH LEVELS
While it possible to alter pH levels to a degree, it is best to grow the plants that do well in the type of soil you are working with. Once a soil test has provided the information you need, use the Internet, a wonderful place for such research, to determine the acidity/alkalinity preferences of various plants. |
| Wisteria | Wisteria | yes |
put coffee grounds around base of plant
in fall: after growth stops apply bonemeal
spring: superphosphate for better bloom OR
general formula: i.e. 5-10-5 (the middle number, phosphorous, higher for flowering) |
DAYLILIES