Definitions

Airlayer: a propagation technique where roots are encouraged to grow on a branch before it is cut off it's mother plant. Most fruit trees are clones & are created this way. 

Allelopathy: some plants produce biochemicals that inhibit the growth of other plants. Black Walnut & Sunflower are the biggest examples in our area. 

Annual: a plant that completes all stages of it's lifecycle in one year. They germinate, grow, flower & fruit in 1 year.

Anther: male flower structure responsible for producing pollen. They are held up by the filament. Together, the filament & anther make up the stamen.

Aphids: are tiny bugs that suck sap from a plant. They are a common plant pest. Sometimes ants will farm them on plants, protecting them & milking them for honeydew. Beneficial insects like ladybugs love to eat aphids.

Biannual: A short lived plant. Some like onion & carrots go through a vegetative stage year 1, then bloom in their second year. Sometimes horticulturists use this term to describe a short lived perennial, or tender perennials that don't overwinter well in a specified growing zone.

Bolt: A period of rapid growth often associated with hot temperatures. Plants experience stress & race to reproduce. After an herb plant bolts, the leaves loose flavor. Cilantro is a good example. Bolted plants can still produce seeds you can save & plant again latter.

Coco Coir: a soil additive made from coconut shell husks. It can add bulk, texture & moisture retention. It is a good alternative to peat, because peat harvest isn't sustainable. 

Cold Stratification: seeds require a period of moisture & cold before they can germinate. This is common in native plants, because they are built for our changing seasons. If a plant germinates at the wrong time of the year they could be killed by frost or cold. This type of dormancy helps native plants germinate & grow at just the right time of the year. The length of cold stratification can vary. 30-60 days is common. 10, 90 or 120 days are less common.

Common Name: these are unofficial names commonly used for plants. These names can vary widely. Often a plant can have multiple common names, or different plants could use the same name. They may be shorter or easier to remember, but scientific names let us know exactly what species we are discussing.

Conifer: a tree or shrub with needle like leaves & reproduce with structures known as cones. Like pinecones.

Cultivar: is a term that refers to specific traits an individual plant has that differ from other's in their species. This is often noted in quotes following a scientific name. Tomatoes are one species. Each variety of tomato with it's own name is a cultivar. The scientific name for corn is Zea mays, but there are lots of different types of corn right? Zea mays 'Dakota Black Popcorn' is a specific type of corn that develops round black seeds that make good popcorn. Most garden crops & flower species have multiple cultivars. These plants may be selected for their growth habit, size, shape, color or any other variation. The proper way this is noted is in in quotes following the plants scientific name. 

• • Nativar: is a cultivar derived from a native plant. These can be deceptive, because you think you are buying a helpful native plant. However, not all nativars relate to other species in their ecosystem the same way as their native parents. They may be bred for aesthetics at the cost of function. There are tons & tons of beautiful native plants, so we prefer to work with the original species whenever possible.

Deadhead: the process of removing spent flowers, before they get a chance to go to seed. There are 2 major reasons to deadhead: aesthetic & control. Removing dead flowers can improve the look of your plants & in many cases, encourages new blooms to grow. Removing these old flower heads can also control the spread of a species by preventing new seeds from falling on the soil to germinate.

Deciduous: types of trees & shrubs who naturally shred their leaves each year. Evergreens are not the opposite, its more of a scale with species at various points inbetween.

Dioecious: a plant species with separate male & female plants. Male plants still have flowers, but they only produce pollen & cannot grow fruit. Female plants must receive pollen from a separate plant in order to produce fruit. Persimmons are this way, so you need both male & female plants in proximity of each other or no fruit will grown.

Edible: it is important to research multiple credible sources before ingesting any new plants. Naturally you want to avoid toxic look-a-likes. Many plants only have certain parts that are edible. Others, like Elderberry must go through a process like heating to remove toxins. Common names can refer to multiple species. Knowing the scientific name is critical. In the Viburnum genus, some have edible uses whereas other family members cannot be consumed. Individuals may react to the same plant in different ways. Many plant species have not been researched enough yet to verify their toxic or medicinal qualities. Doing good research & seeking out professionals is important.

Ephemeral: these are plants that appear for only a short time. In Missouri we have a lot of 'spring ephemerals'. They take advantage of sunlight while most plants are still dormant. Bluebells (Mertensia virginica) & Spring Beauties (Claytonia virginica) pop up at the end of winter under leafless trees. They complete their entire lifecycle within a short period & typically disappear before the end of spring. They enter dormancy while other species grow, then will return the next year.

Epiphyte: plants that grow on other plants but are not parasitic. This is often achieved through unique root systems. Tropical orchids & Holiday Cactus are popular epiphytes. In their native ranges they grown on trees & cliffs. They have smaller root systems & don't need much, if any, soil. Aerial roots are common in epiphytes & allow orchids & holiday cactus to pull moisture out of the humid air instead of the ground.

Evergreen: a tree or shrub that does not annually shed it's leaves.

Fertilizer: plants require various nutrients to complete their various processes. Some species like Corn are heavy feeders, while native Prickly Pear Cactus can grow in really poor soil Each plant is different. When looking for a fertilizer you will notice three numbers, like 10-10-10. The first number represents the ratio of nitrogen (N), the middle is phosphorus (P) & the third is potassium (K). General, all-purpose fertilizers typically have equal ratios. A fertilizer for flowers might show 5-10-5, because phosphorus is an important nutrient for growing flowers. Other mixes might include trace minerals plants use less of like calcium (Ca), sulfur (Si), magnesium (Mg) & others.

• • Compost is often a natural way to provide plants with nutrients, but can take time to breakdown. I'm always skeptical of a product that promises quick nutrition. Most plant & compost matter takes a long time to breakdown Healthy soil without pesticides & full of microorganisms provide the best breakdown of nutrients for plants. 

    • • Source of compost is important. Many farmers use animal waste fertilizer, but if it's not coming from a clean & reputable source it could bring unwanted pathogens with it.

  • Decomposition can happen under aerobic (with oxygen) or anaerobic (without oxygen) conditions. Anaerobic conditions can breed harmful pathogens, where as aerobic decomposition feeds a lot of beneficial bacteria. We humans are built to smell the difference. The classic smell of soil is due to the good bacteria living in it, whereas sour/mildew smells tell us harmful bacteria are growing.

  • Some nutrients can wash out of the soil or can only be absorbed within a certain soil ph range. Theres lots of information out there about the different nutrient needs of specific plants. 

Flower Structures: flowers can be male, female or both. They are responsible for reproduction.

• • Anther: male flower structure responsible for producing pollen.

  • Endosperm: part of a seed created by the 2nd sperm cell in pollen. This becomes the first food source for a germinated seed. It is the portion that contains nutrition in the grains & seeds we eat.

  • Filament: male flower structure that holds up the anther.

  • Ovary: contains eggs of female genetic material. Often latter becomes a fruit that containing seeds.

  • Pistil: female structures in a flower. Made up of ovary, stigma & style.

  • Pollen: male genetic material containing 2 sperm cells. Once it reaches the right stigma, it germinates & grows a pollen tube down the style to the ovary. One sperm cell fertilizes the egg, while the second becomes the endosperm.

  • Stamen: male structures in a flower. Made up of filament & anther.

  • Stigma: female flower structure responsible for receiving pollen.

  • Style: tissue that connects the stigma & ovary, Part of the Pistil.

Forest: a native ecosystem made of mature & understory trees. Shade loving shrubs & herbaceous plants cover the floor. Moisture can vary from medium-dry to moist.

Germinate: the transition from a dormant seed to absorbing water, sprouting & then growth into a seedling. 

GMO: stands for 'genetically modified organism' & refers to plants changed through biotechnology. As with any technology there are a wide range of changes & techniques. GMO seeds are not available for sale to the public. You will see many seed companies bragging about their non-GMO seeds, but the seeds available to the home gardener are non-GMO anyways. Food is a different matter, you can definitely purchase foods at the grocery store that have been genetically modified. 

Heirloom: plants whose seeds can be saved & replanted each year. Seeds are 'true to seed' & will produce similar to their parent plants. This allows certain plants to be passed down through generations. Not everywhere adheres to this definition, so read the fine print. When we define our seeds as 'heirloom' we mean the seeds have been collected from our own plants. When you plant our seeds you can continue saving & planting them for generations.

Hoop House: a temporary frame to hold shade cloth, frost cloth or greenhouse plastic in place over plants. This can extend the growing season or protect plants from pests without chemicals. Pvc & fiberglass rods are common frame options.

Hybrid: a plant developed by cross breading two closely related plants. This is noted within a scientific name using 'x'.

• • Example: Freeman Maple (Acer x fremanii) is the product of a Sugar Maple (A. saccharinum) cross-pollinating with a Red Maple ( Acer rubrum)

Invasive: non-native plants usually with rapid growth. They threaten local ecosystems by choking out life & outcompeting desirable plants. Much of our undeveloped land isn't original native plants, but wastelands of dangerous invasive plants. These species should never be planted & should be removed so they don't continue their assault.

• • Japanese Honeysuckle (Lonicera japonica), Bradford Pear (Pyrus calleryana), Johnson Grass (Sorghum halepense) & Winter Creeper (Euonymus fortunei) are some particularly heinous invasives in the STL region.

Legumes: a group of plants that have evolved an ingenious nutrient relationship. They build structures on their roots called nodules. These become homes for a beneficial bacteria. Nitrogen is the biggest nutrient a plant needs & this good bacteria provides nitrogen to the plant. This allows legumes to grow in areas with poor nutrients & produce food with high protein content. Legumes include many favorite plants: beans, soybeans, peas, lentils, peanuts, redbuds, black locust & many, many more. Clovers are a popular cover crop because of their ability to add nitrogen to the soil. 

• • In the midwest, it is common for farmers to plant corn one year, then soybeans the next. Corn is a heavy feeder that consumes a lot of nitrogen. Soybeans the following year help to add nitrogen back into the soil & the alternation continues.

Light: plants rely on sunlight to produce their energy. Each species, sometimes individuals plants too, have their own light needs. Too much sun can burn a plant's leaves & too little can stunt their growth.

• • Full Sun: 8+ hours of sunlight touching the plant. In St. Louis our summers can bring drought & temperatures in the high 90's or even 100's. For some plants labeled as full sun, that's just too extreme. Fragile full sun plants can benefit from a shade cloth during a heat wave, or a tall companion like okra to give them a little protection.

  • Partial Sun: 4-6 hours of full direct sunlight.

  • Partial Shade: 0-4 hours of direct light, but often enjoy a lot of bright indirect light

  • Full Shade: 0 hours of full direct sun, but many like partial sun like the dappled shade under a tree

  • Photoperiodism: a term used to describe plants that track day length. The function of this ability helps them enter the right growth stage at the right time. Chia, for example, will stay in a vegetative stage until fall. When daylight diminishes to 12 hours, Chia plants are triggered to initiate flowering. 

Monoecious: species with male & female flowers on one plant. Means 'one house'. Some have male & female parts in all of their flowers. Others have two different flowers on each plant (separate male & female flowers). This can be important when figuring out how many of a species you need to plant for pollination & fruit production to occur. Since both flowers are on the same plant, they can all produce fruit & many of them can self pollinate.

Native: plants that have existed within an ecosystem for an extended period of time. This term has a variety of definitions. When we talk about 'native' on this site we are speaking about plant species that have grown here before the colonization of the americas & interact with the local ecosystem. Native plants are essential to maintaining stable ecosystem populations & combating climate change.

• • Native plants hare evolved along side other organisms. Many species depend on specific plant species & their numbers decline due to a lack of resources. Monarch's are famously known to depend on our native milkweed plants. Relationships like this are very common. Many songbirds rely on native insects to feed their chicks. Those insects rely on the right plants.

  • Crops: The 'Native' term has a lot of gray areas. Corn for example was domesticated from the teosinte plant by mesoamericans about 9,000 years ago. By around 4,100 years ago, it spread throughout North America & revolutionized economies. People are the reason corn exists and grows well here, but it has been grown here for so very long. Today, we still live in the era of corn. This plant is deeply embedded in our modern economy & how we feed both people & animals cheaply. Many, many plants owe their expansion to human intervention.

  • Expanding ranges: Like many organisms, plants are programed to procreate. They are constantly fighting for resources & habitats. An abandoned field may allow tree seedlings to become established. Overtime it transitions to woodland then forest. Pioneer species like Eastern Red Cedar & Willow grow where others can't. Slowly changing their environment so other plants can start growing there as well. Fluctuations in our climate allow opportunity for some species to advance their range while limiting the growth & spread of others. In St. Louis, beautiful Southern Magnolias are becoming easier to grow, while our native dogwoods are having a more difficult time. A lot of our own food relies on pollinators to fruit.

Neem Oil: A common, gentile pest control produced by the Neem tree. You can commonly find this online & in garden centers. You often mix it with water & spray onto plants, containers & soil. It can be an organic way to manage pests that is safe for people & pets if not over sprayed. I try to avoid spraying it on flowers, because I don't want to risk hurting pollinators. 2-3 applications often take care of an outbreak, or it can also be used preventatively.

Organic Certification: a farming practice regulated by USDA that avoids using artificial chemical fertilizers or pesticides. Certification requires a farm be inspected & meet specific standards. Organic gardening practices often seek to work with nature & other organisms instead of against it.

Organic Matter: partially decomposed plant material bulks up the soil & slowly releases nutrients as it continues to break down. The USDA notes there can be billions of microorganisms in a healthy teaspoon of soil. More microbes than people on earth in each teaspoon! They are responsible for turning organic matter into energy forms plants can access. 

Peat Moss: a common, but unsustainable ingredient in many soil mixes. Peat bogs are slow growing, unique ecosystems that capture tons of carbon. Harvesting it destroys these ecosystem, releases it's stored carbon & is shipped long distance. There are better, less damaging soil additives.

Perennial: A plant that lives longer than 1 year. They will return each year. Many go dormant in the winter here.

Perfect Flower: a single flower that contains both pollen producing male organs & egg producing female organs. This is common in older species of flowering plants, like Magnolias.

Perlite: volcanic glass that is popped like popcorn & is an additive to soil mixes. Perlite helps a soil drain well & is common in cactus & succulent mixes. Since I tend to overwater, I find adding perlite to my container soils helps prevent root rot. I also like it as the majority of a propagation medium. It can help soil stick to new forming roots, whereas vermiculite holds more moisture but doesn't stick well to plant roots. Perlite will float in water. Avoid any dust, misting can help. Perlite for organic use can easily be found. 

PH: a quality of soil from acidic to alkaline. Many plants prefer specific PH ranges that allow them to access nutrients. Some elements a plant needs to grow are only available at certain PH ranges. PH stands for 'Potential Hydrogen' & is measured with a scale from 0-14. 

• • Acidic: a ph of 0-5 refers to something acidic. Stomach acid & lemon juice have a PH around 1. You can purchase many products designed to increase the acidity of the soil Sulfur is one ingredient used in these products. Azalea & rhododendrons prefer more acidic soils to bloom.

  • Neutral: ~6-7 on a PH scale. Pure water has a neutral PH.

  • Alkaline: a ph of 7-14. Sea water is around 8 & baking soda around 9. Lime (from limestone) is a common soil amendment that can be used to raise the PH.

  • St. Louis PH: Most of Missouri, including St. Louis exist on top of massive calcium limestone deposits. This is why our water is so hard. It also gives our water & soil more alkaline PH than other areas. Gardeners here may need to amend soils for plants with acidic needs. Most soils here have a PH of 6.3-7.2 Bonus Fact: Rain water is often slightly acidic while our groundwater is more alkaline.

  • Chlorosis: plant nutrient deficiency. Veins may remain green, while rest of leaf goes pale or yellow. Sometimes it looks like a wild new variegated leaf, or they can brown as well. PH affects what nutrients are available to a plant. Plants with chlorosis cannot access iron or magnesium. These nutrients very well could be in your soil already. If you notice chlorosis on your plants, especially trees, research that plant's preferred PH range. There are many at home test options or you can send a soil sample to be tested. If your soil isn't the plants ideal range, you can amend the soil. If your soil is within the ideal PH range, then you may need to add iron or magnesium to remedy the chlorosis.

  • Hydrangeas: PH can change the flower color of two hydrangea species. An acidic soil with a PH of 0-6.5 will produce blue or purple blooms. Alkaline soils of 7.5 & above produces pink flowers. There are even fertilizers available for specific hydrangea color aspirations.

    • • Bigleaf Hydrangea, Hydrangea macrophylla

      • Mountain Hydrangea, Hydrangea serrata

Pioneer Species: hardy plants that can grow where other plants can't. Overtime they change their environment in ways that allow new species to grow. Think of Eastern Red Cedars growing along interstate cliffs or willows in soils that are too wet.

Powdery Mildew: a plant disease often occurring in dry/warm places. It looks like a whitish gray powder or smear over the leaves. It's common on showy flowers like peony in late summer. It also shows up on Zinnia if the plants get too much moisture. Management techniques include removing damaged plant matter, neem oil, reduced watering & avoiding overhead watering.

Prairie: ecosystem dominated by grasses & herbaceous plants in full sun. Plants typically have deep roots & drought tolerance. They have the most organic matter of any ecosystem due to the amount of plant material that sheds off each year. Rubisco is an enzyme plants use to photosynthesize. It's not very efficient though. Plants like grasses have developed a better form of photosynthesis & are known as C4 plants. This trait allows them to grow in places too dry or elevated for trees to establish. Hence the Great Plains plateau of North America or the Savannah grasslands in Africa. Here we have both short grass and tall grass prairies. 

• • Tall Grass Prairie: An important & endangered ecosystem in central North America. Dominated by four native grasses: Big Bluestem (Andropogan gerardii), Little Bluestem (Schizachyrium scoparium), Indian Grass (Sorghastrum nutans), & Switchgrass (Panicum virgatum). Many flowering perennials grow along with these grasses. Together they provide shelter & food for so many pollinators, beneficial insects, birds & mammals.

Riparian: a wet ecosystem along river edges, pond edges or in flood plains. Light can vary, but these plants typically have a high tolerance for wet soils.

Rust: is a fungal infection that can harm plants. It appears as rusty red spots on the plant. Heat & humidity are it's best friend, so it is common here in St. Louis. It affects some species more than others & typically becomes an issue by mid summer. Providing good airflow is a helpful preventative measure. Think about how closely plants are grown to each other. Pruning can increase airflow & help the leaves dry out. Some other ways to manage rust infection: neem oil spray, chamomile spray, destroying infected plan material & avoid overhead watering that gets the leaves wet.

• • In my garden, Hollyhock is one of the plants most susceptible. Rust can prevent flowering or even kill the whole plant. Come summer, I make sure to regularly remove nearby weeds & prune any damaged or congested leaves. I also regularly apply neem &/or chamomile.

Scarification: a technique some seeds require so they can germinate. These seeds have a complex dormancy to prevent them from prematurely germinating. Scarification is the process of unlocking that dormancy so the seed can absorb water & germinate. Scarification techniques can vary by species. Okra need to be gently rubbed with sandpaper. Other's may need boiling water, a file or a special acid before the seed can absorb water.

Scientific Name: official, universal two-part name used to refer to one single species. The first name is the genus & refers to a group of close relatives. The second is called the Specific Epithet & refers to specific individuals within a genus. The species or scientific name requires both genus & specific epithet. DNA sequencing has allowed scientists to verify relationships, so some plants will have updated scientific names.

Soil Moisture: its important to know that most plant roots need oxygen to prevent root rot. I find it helpful to think of soil moisture on a scale. Some plants are happy at only one level, while others can tolerate a range. A wooden skewer or a toothpick (for small pots) is good for identifying how moist a container is. Insert it into the soil, remove & check the moisture line.

• • 1 : Can't dry out. These are very thirsty plants that tolerate long periods of standing water. They can often be found along the edges of waterways. Drought can cause major damage.

  • 2 : Prefer not to dry out. Tolerates short periods of standing water. These type of plants are common in flood zones.

  • 3: Want constant moisture, but must drain well. Avoid standing water. Pay these plants special attention during dry spells.

  • 4 : Medium-Wet. Grow in well draining soil. Avoid standing water & droughts. Most garden veggies fall in this range.

  • 5: Medium-Dry. Typically have drought tolerance, but does better when watered during dry spells. Avoid standing water & allow soil to dry out from time to time. Snapdragons can tolerate drying out, but they have very little tolerance for over watering. Too much moisture will cause their leaves to yellow & fall off.

  • 6: Requires Dry. Allow soil to completely dry out before watering. These plants have high drought tolerance & too much moisture quickly causes root rot. A good example is my English Lavender. It lives in rock piles outside & I try very hard to never water it.

Spider Mites: tiny microscopic insects that thrive in dry conditions inside or outside. They can build tiny cobwebs & stunt a plants growth. Look closely at the growing ends, because this is where damage often occurs. Some techniques I find helpful include: soap & water, keeping plants moist/misted, neem oil & cleaning/quarantining new plants coming indoors. Spring & Fall are when most of their damage happens. In the early days of Spring you may see tiny red moving dots, that's them too.

Succulent: refers to a type of leaf, not a group of plants. These leaves are usually thick & store a lot of water. Because of their water efficiency, succulents can often survive long periods of drought. Think cactus & all the indoor plants we refer to as 'succulents'. Holiday cactus also have succulent leaves even though they grow in wet tropical areas. Their water conservation allows them to grow on other plants without soil.

Taproot: a type of root where plants grow a large central root that grows deep into the ground. This root system can help a plant tolerate drought. Due to the deep root, plants can be sensitive to transplanting. Mature plants can be difficult to divide. If you are planting a species with a taproot, be gentle. Some may require direct sowing, or a young transplant age.

Temperature: most plants do well within specific temperature ranges. Nightshades like tomatoes need warm soil temperatures of 80F+ to grow. Snapdragons grow best in temperatures of 32-75 F. Most plants shut down when temperatures are 98 F+.

• • Cool Season Plants: These plants grow best during the cool temperatures of spring & fall. Many have high frost tolerance & will grow on any nice winter days. They often disappear or stop growing during summer heat. Some of my favorites are Snapdragons, Carolina Geranium, Purple Dead Nettle, Henbit & Violets.

  • Warm Season Plants: Plants that grow best spring through fall. Many require warm soil temperatures to grow & will die or go dormant when cold weather arrives. Most of our traditional garden crops fall in this group.

    • • A note on Grasses: both ornamental & lawn grasses fall into warm or cool season categories. This means they are often ugly and dead looking when its not their season. Choosing the right mix, perhaps species from both groups, can help your lawn stay green longer.

Tender Perennial: a plant that does not complete it's lifecycle within 1 year, but doesn't live very long. Some species just have short lifespans. Others just don't like growing here. Our winters or temperature swings might be too much. This term could also describe a plant at the very edge of it's native range. Tender perennials can benefit from being planted in a protected area or winter mulching.

True to Seed: seeds that when planted, have similar desirable traits as their parents. Heirloom seeds are supposed to be true to seed so that you can collect seeds & grow new plants for generations. Many cultivars & fruit trees are clones of each other. If you collect & grow their seed, they will not produce seedlings with similar traits to their parents.

Variegated: a leaf with two or more colors. This is common as cream edged leaf with a green center. Others can be striped. In pothos, is shows up as random patches of cream or gold.

Vermiculite: a naturally occurring mineral that is mined & commonly added to soil mixes. Vermiculite can hold onto moisture & fertilizer. It is commonly used in mixes to help with water retention in potted plants. Vermiculite for organic methods can easily be found.

Weed: I don't like this term. It is over used to describe unknown or unwanted plants. This is lazy & dangerous. Edible, forageable, medicinal & culturally significant plants are too often given this name, which marginalizes the populations who use them. Goldenrods (Solidago species) are often called weeds & improperly accused of causing allergies. The truth is that their pollen is too big & heavy to get in the air and cause allergies. Solidagos are native, they belong here, grow well here & have tons of ecosystem connections. In bloom they are just loaded with happy pollinators. The name 'solidago' means to make whole, to heal. It has a history of use in a tea or as medicine. 

Woodland: Smaller trees provide open, dappled sunlight or transitions between forest & other ecosystems. Shrubs & herbaceous plants grow around them. Plants can range from full sun to full shade.

Xeriscape: An ecosystem with plants that like sunny, rocky & or dry conditions.