Plants

Plant category. Library of general plant articles including care and growing tips.

What are Insoluble Calcium Oxalate Crystals?

by
What are insoluble calcium oxalate crystals?

What are insoluble calcium oxalate crystals?

Insoluble calcium oxalate is a type of biomineral that is commonly found in plants and is made up of small, crystals of calcium and oxalate. These crystals are insoluble in water and other solvents and can accumulate in various tissues and organs of plants. Insoluble calcium oxalate (CaOx) crystals are the most abundant biomineral in plants¹ that can be found in the leaves, stems and roots of over 200 plant families.

The discovery of calcium oxalate crystals was made in the mid-17th century by Marcello Malpighi (1628-1694), an Italian physician, biologist, and anatomist. Dr Malpighi used the newly-invented microscope to examine the internal structure of plants and described them his work ‘Anatome Plantarum‘, which was published in 1675. In his book, he refers to calcium oxalate crystals as ‘sarmenta‘, which he observed in the stems, leaves and roots of a number of plant species.

Calcium oxalate crystals are found in five morphologies:

  • Raphides (needle-shaped crystals)
  • Druses (spherical aggregate of individual crystals)
  • Styloids (elongated crystals with ridged or pointed ends)
  • Prismatic (four or more sides similar in length and width)
  • Crystal sands (minute crystals in a single cell).

The focus of this article is raphides, which pose the greatest risk to humans and animals due to their shape which allows them to penetrate the tissues of the oropharynx and gastrointestinal tract. They can vary in size from micrometres to several millimetres and may be straight, clustered in groups, curved or spiral shaped or branched with multiple needle-like projections.

Read more

Is Bleeding Heart (Dicentra) Toxic to Dogs?

by
Is bleeding heart toxic to dogs?

Bleeding heart (Dicentra spp., andLamprocapnos spectabilis) is toxic to dogs. The toxic principle is isoquinoline alkaloids, a convulsant and irritant sap that can cause skin irritation and ocular pain. Alkaloids are secondary metabolites that are organic compounds produced by the plant that are not directly involved with growth, development or reproduction. Secondary metabolites have several functions including cooperating with other species, such as flowers that attract insects necessary for pollination or to repel pests including plant-feeding insects and animals and pathogenic microorganisms.

Read more

Etiolation In Plants

by
What is etiolation?

What is etiolation?  Ι   When is etiolation normal?  Ι   Signs of etiolation   Ι  Culinary etiolation   Ι  Etiolation in agricultural crops  Ι How to prevent etiolation in plants

What is etiolation?

Etiolation (ee-tee-oh-lation) is a phenomenon that occurs in plants that grow in limited or absent light. This triggers the elongation of cells at the growth tip to help the plant reach a potential light source. The word etiolate is derived from the French word Ă©tiolĂ©, which means ‘to blanche’, referring to the pale colour of the plant.

An example of etiolated plants can be seen when you lift an object from the ground and find white plants beneath it. This is because these plants have been growing in darkness and have elongated cells to reach for the light.

Read more

Propagating Plants in Water

by
Propagating plants in water

Water propagation is one of the easiest ways to propagate plants. One of the advantages of water propagation is you can see when the plant has formed new roots, unlike soil propagated plants.

Read more

Is Madagascar Periwinkle Toxic to Dogs?

by
Is Madagascar periwinkle toxic to dogs?

Madagascar periwinkle (Catharanthus roseus) is toxic to dogs. The toxic principle is vinca alkaloids which can cause hypoglycemia (low blood sugar), hypotension (drop in blood pressure), incoordination, tremors and seizures.

Read more

Winter Flowering Plants

by
Winter flowering plants

Spring and summer are traditionally the seasons we expect to see a vibrant collection of flowering plants in the garden, but there are some plants that flower in winter, providing some much-needed colour in the house or the garden.

Climate plays a role, for example, it is mid-winter here in Sydney, but it is not uncommon for geraniums to flower year-round, and I currently have delphinium and cosmos in bloom. Colder climates will have fewer flowering plants, but there are still a number of plants that can be enjoyed, even in cool climates.

Read more

Which Seeds Need Light to Germinate?

by
Which seeds need light to germinate?

There are a number of factors that trigger seeds to germinate just at the right time to enhance their survival. All seeds need moisture and oxygen to germinate, and the preferred soil temperature varies from plant to plant. In addition, some seeds need cold stratification, scarification, darkness or light. If these factors are not in place, germination will not occur, or if it does, it will be lower than expected.

Read more

Are Roses Toxic to Dogs?

by
Are roses toxic to dogs?

Roses (Rosa spp.) are non-toxic to dogs. These garden and cut flower favourites are safe to keep around dogs and make a great choice for the garden and as a cut flower.

Interestingly, the fruit that grows on the blossom of a wild rose (Rosa canina) known as rosehip contains antiinflammatory properties and is commonly used to treat arthritis in dogs.

Read more

Winter Jobs for the Garden

by
Winter jobs for the garden
  • Weed
  • Clear grass and weeds from around trees and mulch
  • Top up potted plants
  • Re-pot pot bound plants
  • Remove annuals
  • Clean gutters
  • Plant roses
  • Prune trees and shrubs
  • Maintain garden tools
  • Pressure clean hard surfaces
  • Remove annuals
  • Clean gutters
  • Order spring seeds
  • Cold stratify seeds

It’s tempting to bunker down indoors during the cold months but winter is the perfect time to prepare your garden for the spring and summer ahead.

Read more

Optimal Soil Temperature For Flower Seed Germination

by
Optimal soil temperature for flower seed germination

Seeds are in a dormant state until the right conditions occur which triggers the end of dormancy. There are a number of critical factors that determine when a seed will germinate including moisture, oxygen and the right soil temperature. Some seeds also require a period of cold, known as cold stratification. This mimics the normal winter a seed would usually experience before germinating once temperatures warm up in spring.

We recommend gardeners purchase a soil temperature thermometer to check soil temperature before sowing seeds. These are available from most nurseries or online.

Celsius

Fahrenheit

Stratification?

African daisy (Arctotis stoechadifolia) 18 – 21 65 – 70 No
African daisy (Osteospermum spp.) 21 – 24 70 – 75 No
Alyssum (Lobularia maritima) 12 – 23 55 – 75 No
Amethist flower (Browallia spp.) 18 – 21 65 – 70 No
Aster (Aster spp.) 18 – 23 65 – 75 No
Baby’s breath (Gypsophila spp.) 15 – 18 60 – 65 No
Balloon flower (Platycodon grandiflorus) 16 – 20 60 – 68 No
Bear’s breeches (Acanthus mollis) 18 – 21 65 – 70 No
Bee balm (Monarda didyma) 16 – 21 60 – 70 No
Begonia (Begonia spp.) 18 – 21 65 – 70 No
Bellflower (Campanula spp.) 21 – 23 70 – 75 Yes
Bells-of-Ireland (Moluccella laevis) 13 – 18 55 – 64 Yes
Black-eyed Susan (Rudbeckia hirta) 18 – 21 65 – 70 Yes
Bleeding heart (Dicentra spectabilis) 4 – 12 40 – 55 Yes
Boltonia (Boltonia spp.) 18 – 21 65 – 70 No
Borage (Borago officinalis) 18 – 29 65 – 85 No
Bugle flower (Ajuga spp.) 10 – 15 50 – 60 No
Bugloss (Anchusa capensis) 18 – 21 65 – 70 No
Butter daisy (Melampodium
paludosum)		 18 – 21 65 – 70 No
Butterfly flower (Schizanthus spp.) 18 – 22 65 – 71 No
Butterfly weed (Asclepias tuberosa) 18 – 24 65 – 75 Yes
Calendula (Calendula officinalis) 18 – 21 65 – 70 No
Californian poppy (Eschscholzia californica) 12 – 21 55 – 70 No
Candytuft (Iberis spp.) 23 – 29 75 – 85 No
Canterbury bells (Campanula medium) 18 – 21 65 – 70 Yes
Cape jewels (Nemesia strumosa) 13 – 18 55 – 65 No
Carnation (Dianthus spp.) 15 – 21 60 – 70 No
Catnip/catmint (Nepeta spp.) 18 – 21 65 – 70 No
Chamomile (Matricaria chamomilla) 18 – 21 65 – 70 Yes
Chilean bellflower (Nolana paradoxa) 20 – 22 68 – 72 No
Chinese aster (Callistephus chinensis) 20 – 23 68 – 73 No
Chinese forget-me-not (Cynoglossum amabile) 18 – 20 65 – 68 No
Chinese lantern (Physalis alkekengi) 16 – 21 60 – 70 No
Chrysanthemum (Chrysanthemum spp.) 18 – 23 65 – 75 No
Clematis (Clematis spp.) 20 – 22 68 – 73 Yes
Cliquefoil (Potentilla spp.) 19-21 67-70 No
Cohosh (Cimicifuga spp.) 18 – 21 65 – 70 No
Columbine (Aquilegia spp.) 10 – 12 50 – 55 Yes
Common rockrose (Helianthemum nummularium) 21 – 24 70 – 75 No
Common sneezeweed (Helenium autumnale) 19 – 22 65 – 73 No
Coral bell (Heuchera spp.) 18 – 21 65 – 70 No
Corncockle (Agrostemma githago) 15 – 21 60 – 70 No
Cornflower (Centaurea cyanus) 15 – 21 60 – 70 No
Cosmos (Cosmos bipinnatus) 21 – 25 70 – 77 No
Cup and saucer vine (Cobaea scandens) 21 – 23 70 – 75 No
Cupflower (Nierembergia spp.) 21 – 23 70 – 75 No
Cupid’s bow (Achimenes spp.) 21 – 23 70 – 75 No
Cupid’s dart (Catananche caerulea) 20 – 23 68 – 75 No
Cyclamen (Cyclamen spp.) 18 – 20 65 – 68 No
Dahlberg daisy (Dyssodia tenuiloba) 18 – 21 65 – 70 No
Dahlia (Dahlia spp.) 21 – 23 70 – 75 No
Delphinium (Delphinium elatum) 15 – 20 59 – 68 Yes
Echinacea (Echinacea spp.) 18 – 21 65 – 70 Yes
Edeiweiss (Leontopodium alpinum) 18 – 21 65 – 70 Yes
English daisy (Bellis perennis) 18 – 21 65 – 70 No
Evening primrose (Oenothera spp.) 21 – 26 70 – 80 No
Everlasting (Helichrysum bracteatum) 21 – 24 70 – 75 No
False sunflower (Heliopsis spp.) 21 – 23 70 – 73 No
Fan flower (Scaevola aemula) 20 – 22 68 – 71 No
Firecracker flower (Crossandra infundibuliformis) 21 – 27 70 – 80 No
Flax (Linum usitatissimum) 18 – 21 65 – 70 No
Fleabane (Erigeron spp.) 18 – 21 65 – 70 No
Floss flower (Ageratum houstonianum) 24 – 29 75 – 85 No
Forget-me-not (Myosotis spp.) 18 – 21 65 – 70 No
Foxglove (Digitalis spp.) 15 – 18 60 – 65 No
Garden heliotrope (Heliotropium spp.) 18 – 21 65 – 70 No
Gay feather (Liatris spp.) 18 – 21 65 – 70 Yes
Gazania (Gazania spp.) 15 – 18 60 – 65 No
Gerbera (Gerbera spp.) 21 – 23 70 – 73 No
Geum (Geum spp.) 18 – 21 65 – 70 No
Globeflower (Trollius spp.) 18 – 21 65 – 70 Yes
Glory of the snow (Chionodoxa spp.) 10 – 15 50 – 59 Yes
Gloxinia (Sinningia speciosa) 19 – 21 66 – 70 No
Goldencup (Hunnemannia fumariifolia) 19 – 21 66 – 70 No
Goldenrod (Solidago spp.) 20 – 22 68 – 71 Yes
Goldentuft (Aurinia saxatilis) 15 – 21 59 – 70 No
Hellebore (Helleborus spp.) 18 – 21 65 – 70 Yes
Hibiscus (Hibiscus spp.) 21 – 26 70 – 75 No
Hollyhock (Alcea rosea) 15 – 21 60 – 70 Yes
Iceland poppy (Papaver nudicaule) 18 – 24 65 – 75 Yes
Impatiens (Impatiens spp.) 21 – 23 70 – 73 No
Jacob’s ladder (Polemonium spp.) 18 – 21 65 – 70 No
Laceflower (Trachymene coerulea) 18 – 21 65 – 70 No
Ladys purse (Calceolaria spp.) 21 – 23 70 – 73 No
Larkspur (Consolida ambigua) 10 – 12 50 – 55 Yes
Lavender (Lavandula spp.) 18 – 21 65 – 70 No
Leopard plant (Ligularia spp.) 18 – 21 65 – 70 No
Linaria (Linaria spp.) 12 – 18 55 – 65 Yes
Lisianthus (Eustoma grandiflorum) 22 – 23 72 – 73 No
Livingstone daisy (Dorotheanthus
bellidiformis)		 18 – 24 65 – 78 No
Lobelia (Lobelia spp.) 18 – 23 65 – 73 No
Love-lies-bleeding (Amaranthus caudatus) 20 – 28 68 – 82 No
Lupine (Lupinus spp.) 12 – 21 55 – 70 Yes
Madagascar periwinkle (Catharanthus
roseus)		 24 – 27 75 – 80 No
Marigold (Tagetes spp.) 21 – 23 70 – 73 No
Marshmallow plant (Althaea officinalis) 15 – 21 60 – 70 Yes
Mexican creeping zinnia (Sanvitali procumbens) 18 – 21 65 – 70 No
Mignonette (Reseda odorata) 12 – 14 53 – 57 No
Monkey flowers (Mimulus spp.) 15 – 21 60 – 70 No
Monk’s hood (Aconitum spp.) 12 – 15 55 – 60 Yes
Morning glory (Convolvulus spp.)
 20 – 21 68 – 70 No
Nasturtium (Tropaeolum majus) 15 – 18 60 – 65 No
Nemesia (Nemesia spp.) 12 – 18 55 – 65 No
Nemophila (Nemophila spp.) 12 – 15 55 – 60 No
Nigella (Nigella damascena) 15 – 18 60 – 65 No
Obedient plant (Physostegia virginiana) 18 – 21 65 – 70 No
Pansy (Viola tricolor var. hortensis) 15 – 23 60 – 73 No
Pearly everlasting (Anaphalis margaritacea) 18 – 21 65 – 70 No
Persian violet (Exacum affine) 21 – 24 70 – 78 No
Petunia (Petunia spp.) 18 – 23 65 – 73 No
Phlox (Phlox spp.) 15 – 18 60 – 65 No
Poppy (Papaver spp.) 15 – 20 60 – 68 Yes
Portulaca (Portulaca spp.) 21 – 26 70 – 80 No
Pride of Madeira (Echium candicans) 15 – 20 60 – 68 No
Primrose (Primula spp.) 15 – 18 60 – 65 Yes
Purple rock cress (Aubrieta deltoidea) 18 – 21 65 – 70 No
Queen Anne’s lace (Daucus carota) 16 – 18 60 – 65 No
Rock cress (Arabis spp.) 18 – 21 65 – 70 No
Rudbeckia (Rudbeckia spp.) 21 – 23 70 – 73 No
Salvia (Salvia officinalis) 21 – 23 70 – 73 No
Satin flower (Clarkia amoena) 21 – 23 70 – 73 No
Shooting star (Dodecatheon meadia) 18 – 21 65 – 70 Yes
Sea holly (Eryngium spp.) 18 – 23 65 – 73 Yes
Shasta daisy (Leucanthemum x superbum) 18 – 21 65 – 70 No
Snapdragon (Antirrhinum majus) 18 – 23 65 – 73 Yes
Snow-in-summer (Cerastium tomentosum) 18 – 21 65 – 70 No
Speedwell (Veronica spp.) 18 – 24 65 – 75 No
Spider flower (Cleome spinosa) 21 – 23 70 – 73 Yes
Statice (Limonium sinuatum) 15 – 20 60 – 68 No
Stock (Matthiola incana) 15 – 18 60 – 65 No
Stoke’s aster (Stokesia laevis) 21 – 24 70 – 75 No
Sunflower (Helianthus spp.) 21 – 23 70 – 73 No
Swan river daisy (Brachyscome iberidifolia) 21 – 24 70 – 78 No
Sweet pea (Lathyrus odoratus) 12 – 18 55 – 65 No
Trumpet flower (Incarvillea spp.) 18 – 21 65 – 70 No
Tweedia (Oxypetalum coeruleum) 18 – 21 65 – 70 No
Twinspur (Diascia spp.) 15 – 18 60 – 65 No
Verbena (Verbena spp.) 18 – 23 65 – 73 No
Viola (Viola spp.) 18 – 23 65 – 73 No
Virginian stock (Malcolmia maritima) 18 – 23 65 – 73 No
Wallflower (Erysimum cheiri, syn. Cheiranthus cheiri) 15 – 18 60 – 65 No
Wild indigo (Baptisia spp.) 18 – 21 65 – 70 No
Wishbone flower (Torenia fournieri) 21 – 23 70 – 75 No
Xeranthemum (Xeranthemum annuum) 24-35 75 – 95 No
Yarrow (Achillea spp.) 18 – 21 65 – 70 Yes
Yellow lotus (Nelumbo lutea) 21 – 24 70 – 78 No
Zinnia (Zinnia spp.) 21 – 23 70 – 73 No

Optimal soil temperature for flower germination PDF