Raintree Growing Guide
Plant Propagation
Turning one plant into many — cuttings, layering, division, and seed, and how to choose the right method for what you are trying to reproduce.
AT A GLANCE
Two broad approaches
Vegetative (clones of one parent) and seed (genetic recombination of two).
Easiest to start with
Layering, then division, then softwood cuttings. Seed is easy; seedlings are unpredictable.
Rooting medium
Sterile, low fertility, sharply drained but moisture-holding. Never garden soil.
Critical variable
Humidity. A cutting has no roots and must not lose more water than it can hold.
Time to rooting
Weeks for softwood cuttings; up to three months for hardwood; a full season or more for layers.
Germination expectations
Typically 65–80% of fresh seed germinates; of those, 60–75% make sturdy seedlings.
Best time of day
Early morning, when the parent plant is fully turgid and cuttings are least stressed.
Legal note
Patented and PVP-protected cultivars may not be propagated without a license, even for your own use.
Growing difficulty
Intermediate — simple in principle, but success rates reward attention to detail
Why propagate?
Propagation is how one plant becomes many. For a home grower it is the difference between buying a hedge and growing one, between losing a favorite plant and carrying it with you, between one currant bush and a row of them.
It also teaches you a great deal about how plants actually work. Watching a bare stem push roots into damp sand, or a buried branch root while still attached to its parent, makes the underlying biology concrete in a way that reading about it does not.
âš Before you propagate: check the plant tag
Many modern cultivars are protected. A US plant patent runs 20 years from the application filing date and covers asexual reproduction of that specific cultivar. Plant Variety Protection certificates run 20 years, or 25 years for vines and trees, and can cover seed, tubers, and asexually propagated varieties.
This applies to home gardeners, not just commercial nurseries, and it applies to propagation for your own use or to give away — not only for sale. It also covers every asexual method, not just cuttings: division, layering, rhizomes, and runners are all included. Planting up the daughter plants from a patented strawberry is an infringement in the same way that rooting a cutting would be.
What to look for on a tag or catalog listing:
- PP followed by a number — a granted plant patent. Do not propagate.
- PPAF — plant patent applied for. Protection is pending; do not propagate.
- PVP — a Plant Variety Protection certificate. Do not propagate.
- ™ or ® — a trademark. This protects the plant's name only and does not by itself restrict propagation. Many plants carry both a trademark name and a patent, so check for a patent number separately rather than assuming the ™ tells you what you need to know.
Once a patent expires the plant is free for anyone to propagate. Heirloom, species, and long-established cultivars are generally unrestricted.
Where to check: the plant's own tag or catalog listing is the first place, followed by the breeder or licensor named on it. For a definitive answer, plant patents are searchable through the USPTO's patent database, and PVP certificates through the USDA Plant Variety Protection Office. We can sometimes tell you the status of something we currently carry, but we don't track patent status across the nursery trade and can't verify it on your behalf. When you are unsure and can't confirm it, assume the plant is protected and propagate something else.
The two families of propagation
Every technique below falls into one of two categories, and the difference determines what you end up with.
Vegetative (asexual) propagation
New plants are grown from the vegetative parts of an existing plant — stems, leaves, or roots. Because only one parent is involved, the offspring are genetically identical to it. Clones.
This is the whole point when you have a plant with traits worth keeping. A seedling from your favorite apple will not be that apple; a graft or a rooted cutting will be. Many plants do this naturally — strawberries by runners, raspberries by suckers — and propagators simply direct and accelerate the process.
Seed (sexual) propagation
Pollen from a male part fertilizes an egg in a female part, and a seed results. A seed contains three things: a protective coat, an endosperm that feeds the embryo through germination, and the embryo itself — a young plant in suspension, waiting for conditions worth waking up for.
Seed has real advantages. It is usually cheaper and faster, it is the only route to genuinely new varieties and to hybrid vigor, it is the only viable method for some species, and it avoids carrying certain diseases across generations. The trade-off is that seedlings are not clones: they will differ from their parents, sometimes considerably.
ℹ Saved seed from your own garden
Seed you collect yourself is the product of open pollination by insects or wind, so the resulting plants may look nothing like the parent you collected from. That is not a failure — it is simply how sexual reproduction works. Save seed for the interest of it, not for reproducing a specific plant.
Stem cuttings
Propagation by stem cuttings is the most widely used vegetative method for woody ornamentals, and many favorite shrubs root readily. Tree species are generally harder, though some — crape myrtle, certain elms, birches — can be rooted successfully.
Pacific Northwest
Our climate is unusually kind to propagators. Mild, wet winters west of the Cascades mean hardwood cuttings and outdoor layers rarely dry out and rarely freeze hard enough to be killed, and a shaded cold frame will hold cuttings through winter with very little intervention.
The trade-offs are cool springs and persistent damp. Soil here warms slowly, so seed sown outdoors too early sits in cold, wet ground and rots rather than germinating — bottom heat indoors is worth more than an early sowing date. Ambient humidity also means rot is a likelier failure mode here than desiccation, so err toward sharper drainage and better airflow than a guide written for a drier climate would suggest.
East of the Cascades the reverse applies: humidity is the scarce resource, so cover cuttings more thoroughly and check moisture more often.
You do not need a greenhouse
What you need is high humidity around the cutting. A flowerpot covered with a clear plastic bag, or a bottomless milk jug set over the pot, works for small numbers. For more, use a tray with drainage holes covered by clear plastic stretched over a wire frame. The plastic holds humidity and slows water loss from leaves that have no roots to replace it.
Choosing the material
Take cuttings from the current or previous season's growth on a healthy, disease-free plant, preferably from the upper portion. Several details make a measurable difference:
- Avoid material carrying flower buds. If you must use it, strip the flowers and buds so the cutting's energy goes into roots rather than blooms.
- Do not take cuttings from plants showing nutrient deficiency — but heavily fertilized plants, especially with nitrogen, also root poorly.
- The parent plant should not be under moisture stress.
- Cuttings from young plants root at higher rates than those from old, mature ones.
- Lateral shoots often root better than terminal shoots.
Taking and preparing cuttings
Collect in early morning, when the plant is fully turgid. Keep the material cool and moist until you stick it — a cooler or a dark plastic bag with damp paper towels will do. If there will be a delay, store the bagged cuttings in the refrigerator.
Terminal sections are best, but a long shoot can be divided into several cuttings of 4 to 6 inches. Use sharp bypass pruners or a clean grafting knife; a crushed cut heals poorly. Disinfect the blade between plants with rubbing alcohol or a one-part-bleach-to-nine-parts-water solution so you are not moving disease from plant to plant.
Strip the leaves from the lower third to half of the cutting. On large-leaved plants, cut the remaining leaves in half to reduce water loss and save space. Species known to be difficult should be wounded — a shallow scrape along one side of the base — to expose more cambium.
Rooting hormone
Root-promoting compounds are genuinely useful on species that are otherwise reluctant. Decant what you need into a separate container rather than dipping cuttings into the main supply, and discard the leftover instead of returning it — this prevents contaminating the whole jar. With powder formulations, tap the cutting to knock off the excess before sticking.
Medium and aftercare
The rooting medium must be sterile, low in fertility, and well drained enough to stay aerated, while holding enough moisture that you are not watering constantly. Coarse sand works, as do equal-parts mixes of peat and perlite or peat and sand. Vermiculite alone is not recommended — it compacts and holds too much water. Moisten the medium before use.
Insert cuttings one-third to one-half their length, keeping them right way up with the buds pointing skyward. Space them just far enough apart that every leaf gets light. Water again after sticking if the container is 3 inches deep or more, then cover with plastic and set in bright indirect light — never direct sun. Keep the medium moist, and mist regularly if you can.
Rooting time varies by species, cutting type, and conditions. Conifers take longer than broadleaved plants; late fall or early winter suits them, and once rooted they can stay put until spring.
âš Do not plant rooted cuttings straight into the garden
A newly rooted cutting has a root system far too small for open ground. Pot it up or move it to a nursery bed and grow it on to a decent size first. Survival rates when transplanting to a permanent position improve enormously.
Root cuttings
Some plants will regenerate from a section of root alone. Root cuttings are taken from woody plants during dormancy, when stored carbohydrate levels are at their highest. Depending on species, the cutting either pushes new shoots first and roots afterward, or the reverse.
Plants that respond well include raspberry, blackberry, rose, crabapple, fig, lilac, and sumac. Some plants with underground corms — rhubarb among them — can simply be split or quartered instead.
Large-rooted plants
These are normally handled outdoors. Cut roots into 2 to 6 inch lengths, making a straight cut on the end nearest the crown and a slanted cut on the far end. That is not decoration: it is how you keep track of which way is up, and polarity matters. Bundle cuttings with matching ends together, then store for three weeks in moist sawdust, peat, or sand at about 40°F. Plant them 2 to 3 inches apart in well-prepared soil, with the crown end 2 to 3 inches below the surface.
Small-rooted plants
Cut into 1 to 2 inch sections, lay them horizontally on the surface of the medium in a flat, and cover with about half an inch of soil or sand. Enclose the flat in a plastic bag or cover it with glass, set it in shade, and remove the cover once shoots appear.
Layering
Layering roots a stem while it is still attached to the parent plant, which is why it is the most forgiving method available to a beginner. The stem continues to receive water and nutrients throughout, so the water stress that kills so many cuttings simply never arises. Some plants layer themselves without any help.
Wounding the stem where you want roots to form improves results, and the rooting zone needs both air and steady moisture.
Simple layering
Bend a low, flexible stem down to the ground. Bury a section of it, leaving the last 6 to 12 inches above the surface, then bend that tip upright and stake it there. The sharp bend alone often triggers rooting; wounding the underside of the bend helps further. Almost any plant with low branches is a candidate.
Do it in early spring using a dormant branch, or in late summer using mature wood. Check periodically for moisture and for roots. It may take one season or more before the layer is ready to sever and transplant.
Tip layering
A variation for plants that do this naturally. Dig a hole 3 to 4 inches deep, insert the tip of a current-season shoot, and cover it. The tip grows downward, turns sharply, and grows back up; roots form at the bend and the re-curved tip becomes the new plant. Remove and plant in late fall or early spring. Purple and black raspberries and trailing blackberries are the classic examples.
Compound layering
Also called serpentine layering. Same principle as simple layering, but a single long stem is alternately buried and exposed along its length, yielding several new plants. Each buried section needs at least one bud covered and one bud exposed. Wound the underside of every section you bury.
Growing from seed
Start with good seed from a reliable source, choosing varieties suited to your area that will mature before an early frost. Buy only what you will use in a season — some seed keeps for years, but germination declines.
Quality seed is clean: no other crop seed, no weed seed, no debris. The packet should tell you the variety, the year it was packed, the germination percentage you can expect, and any chemical treatment applied.
Store surplus seed cool and dry. Laminated foil packets hold their own; paper packets should go into a sealed container at around 40°F in low humidity. The door shelf of a refrigerator works well.
What germination requires
A seed will germinate when its internal requirements are met — a mature embryo, enough endosperm to sustain it, and sufficient hormone to start the process — and when four environmental conditions line up.
Water
The first step is imbibition, the absorption of water through the seed coat. What matters is not just presence of water but continuous availability: once germination has begun, a dry spell can kill the embryo outright.
Light
Some seeds need light to germinate, some are inhibited by it, and many are indifferent. Ageratum, begonia, browallia, impatiens, lettuce, and petunia want light; peas, beans, calendula, centaurea, annual phlox, verbena, and vinca prefer darkness. Seed packets usually say.
For light-requiring seed, do what nature does and leave it on the surface, or cover very lightly with fine peat or fine vermiculite, which admit some light. Indoors, fluorescent fixtures suspended 6 to 12 inches above the flat for 16 hours a day work well; higher-intensity lights cost more but produce noticeably sturdier seedlings.
Oxygen
Seeds respire even while dormant, and respiration climbs steeply during germination. The medium must be loose and well aerated. Compacted or waterlogged medium starves the seed of oxygen and germination stalls or fails.
Temperature
Temperature affects both the percentage that germinate and how quickly. Some species tolerate a wide range; others are narrow. Tomato, for example, has a minimum around 50°F and a maximum around 95°F, but germinates best near 80°F. For most plants, 65 to 75°F is the working range.
Published germination temperatures are optimums unless stated otherwise, and they need to be held around the clock — not just during the day. Heat mats, cables, or a warm shelf make this practical.
Transplanting seedlings
Unless seed was sown into individual cells, seedlings must be moved to give them room. The single most common mistake is leaving them in the seed flat too long.
Transplant while they are small, usually as the first true leaves appear above or between the cotyledons — the seed leaves that emerged first. Do not wait until plants are hard and stunted, or tall and leggy.
- Lift the seedlings gently with a wooden plant label or a dibber and let the clump fall apart.
- Handle seedlings by a leaf, never by the stem. A crushed stem is fatal; a damaged leaf is not.
- Ease clumps apart in small groups first, then separate individuals, avoiding torn roots.
- Make a hole deep enough to set the seedling at the depth it was already growing.
- Space small or slow growers about an inch apart; fast, large seedlings about two inches.
- Firm the medium, water gently, and keep the transplants shaded for a few days or under fluorescent light, away from direct heat.
A few plants resent transplanting and are better sown where they will grow, or directly into individual containers: peas, beans, carrots, beets, chard, zinnias, and the cucurbits such as melons and squash.
Hardening off
Hardening is the process of toughening plants raised indoors so they can withstand outdoor conditions. Skipping it causes a severe check in growth, and the risk is highest with early crops facing unsettled weather.
The method is to gradually lower temperature and humidity and reduce water. This drives carbohydrate accumulation and thickens cell walls, converting soft, succulent growth into firmer, harder tissue.
Begin at least two weeks before planting out. Move plants to a 45–50°F space, indoors or in outdoor shade — a cold frame is ideal. Start them shaded outdoors, then move them gradually into sun, increasing exposure a little each day. Keep tender seedlings in on windy days and whenever temperatures fall below 45°F. Water less often to slow growth, but never let plants wilt.
âš Hardening can be overdone
The goal is to slow growth, not stop it. Pushed too far, some crops never recover: cauliflower hardened too severely will form thumb-sized heads and go no further, and cucumbers and melons simply stop growing. Ease off if plants stall.
Note also that even cold-hardy plants are damaged by freezing temperatures before they have been hardened. Properly hardened, they will shrug off a light frost.
Grafting
Grafting joins two plants into one. Rather than crossing two parents to produce a hybrid seed, it takes the roots and lower trunk of one plant — the rootstock — and unites them with a shoot from another — the scion. The result carries the fruiting characteristics of the scion on a root system chosen for size control, soil tolerance, or disease resistance.
It is the standard method for fruit and nut trees, and it is why a dwarf apple is dwarf: the variety on top has nothing to do with the tree's final size. Our rootstock guide covers how that relationship works and how to choose, and our combination tree guide covers managing several grafted varieties on a single trunk.
Common problems
Cuttings wilt and collapse within days
Most common failure
A cutting has no roots and cannot replace water lost through its leaves. Almost every rapid failure is a humidity failure.
- Cover the container with clear plastic and keep it covered.
- Reduce leaf area — strip the lower leaves and halve large remaining ones.
- Move out of direct sun into bright indirect light.
- Mist regularly; keep the medium moist but never saturated.
Cuttings rot at the base
Moderate — medium or hygiene
Blackening and softening at the cut end, often with a sour smell. Usually too much water, too little air, or contaminated tools.
- Switch to a sharper-draining medium; avoid vermiculite alone, which compacts.
- Use a sterile medium — not garden soil.
- Disinfect cutting tools between plants.
- Make sure containers drain freely and are not standing in water.
Seed fails to germinate
Moderate — usually fixable
Nothing emerges, or emergence is thin and uneven. Bear in mind that 65–80% is a normal germination rate even under good conditions.
- Check the light requirement — surface-sow light-requiring seed rather than burying it.
- Hold the recommended temperature 24 hours a day, not just during daylight.
- Keep moisture continuous; a dry spell after imbibition kills the embryo.
- Loosen the medium — compaction starves seed of oxygen.
- Check the packing year on old seed.
Seedlings tall, pale, and floppy
Moderate — light and spacing
Stretched stems and weak growth, often with seedlings leaning toward a window. Insufficient light, excessive warmth, or overcrowding.
- Lower fluorescent fixtures to 6–12 inches above the plants and run them 16 hours a day.
- Transplant on time — leggy growth often means the flat was left too long.
- Give each seedling enough space that its leaves receive light.
- Reduce temperature slightly once seedlings have emerged.
Transplants stall after planting out
Low — hardening
Plants that looked healthy indoors sit still, discolor, or check badly after being planted in the garden.
- Harden off over at least two weeks before planting out.
- Increase outdoor exposure gradually rather than all at once.
- Avoid planting out during wind or when temperatures drop below 45°F.
- If plants have stalled from over-hardening, resume normal water and warmth and give them time.
Seasonal care calendar
Winter
Dec - Feb
- Take hardwood cuttings from dormant deciduous shrubs and vines
- Take root cuttings while carbohydrate reserves are highest
- Order seed; check packing dates on anything held over
- Conifer cuttings taken in late fall can stay in the rooting frame
Early Spring
Mar - Apr
- Sow seed indoors under lights at 65–75°F
- Start simple layers on dormant branches
- Divide crowns and corms — rhubarb among them
- Plant out stored root cuttings
Late Spring
May - Jun
- Transplant seedlings at the first-true-leaf stage
- Begin hardening off at least two weeks before planting out
- Take softwood cuttings from new growth
- Plant hardened transplants into the garden
Summer
Jul - Aug
- Take semi-ripe cuttings as this season's growth begins to firm
- Start tip layers on raspberry and trailing blackberry canes
- Start late-summer simple layers on mature wood
- Keep rooting frames shaded and humid through hot weather
Fall
Sep - Oct
- Sever and transplant successful layers
- Take conifer cuttings — late fall suits them well
- Pot up rooted cuttings; do not plant them straight into the garden
- Collect and clean seed for stratification
Late Fall
Nov
- Move rooted young plants into a nursery bed or protected frame
- Clean, disinfect, and store propagation tools and containers
- Store surplus seed cool and dry at around 40°F