How to Make Hybrid Plants

Assessing Plants to Breed

Select 2 plants of the same category to combine. While there are a few exceptions, you cannot cross-breed species of plants that are in different categories. In other words, you can cross-breed 2 species of seed-bearing plants, trees, vegetables, or flowers, but you cannot mix and match. Select 2 existing species to combine based on what you are capable of growing indoors or in your garden. In general, it is easier to cross-pollinate flowers and graft trees, shrubs, and hardwood plants. Cross pollination is the process of using one species of plant to pollinate another plant of a different variety. Good plants to cross-pollinate include varieties of beans, orchids, roses, and peppers. Grafting is the process of cutting a portion of one species and physically attaching it to a different species. Any plant with a stem can be grafted, but hardwood varieties, like juniper, birch, and citrus trees are best. For flowering plants to be bred together, they must have some overlap in their blooming period. For example, Athena peonies bloom in the early spring, while Bartzella peonies bloom in the early summer. These 2 plants cannot be bred together.Tip: You can only cross-pollinate vegetables that are in the same species. For example, you cannot cross-pollinate broccoli and squash, but you could cross-pollinate squash and zucchini, since they’re related. Two species of carrot can be cross-pollinated, but carrots and broccoli cannot be combined.

Cross-breed weaker varieties of plants to make them stronger. There are many advantages to creating hybrid plants. Genetically-diverse plants tend to be more resilient, stronger, and less prone to diseases. Breed strong species of plants with weaker varieties to improve the weaker plant’s resilience in your garden. For example, if you have French roses that have been struggling to thrive in your garden, cross-breed them with cabbage roses to improve the odds that they grow strong in your garden. It is typically better to combine flower varieties that are different varieties of the same species. If you have hot peppers that have been dying fairly quickly but your sweet peppers have been growing well, cross-breed the 2 species together to create a hot and sweet variety that will have a better chance at surviving.

Combine different vegetable plants to produce unique flavors. If you’re growing herbs or vegetables in your garden, combining different varieties can create some unique flavors. For example, grafting potato roots to a tomato plant can create tomatoes with a vibrant, unique flavor profile. You can also cross-breed different peppers to create new spices and levels of heat. Experiment with different plants in your garden to create unique varieties. If you combine hot peppers and sweet peppers, you will end up with a variety that is moderately spicy with a uniquely sweet taste!

Using Cross Pollination

Identify 1 male plant and 1 female plant to cross-breed. Grab a magnifying glass and head out to your garden or plant nursery. For flowers, male plants have stamens, which produce the pollen used to breed. Stamens typically look like long stalks that extends away from the plant. Some flowers have 5-6 stamens. Female plants have pistils, which are thinner, shorter stalks that are always located in the center of the flower. For vegetable and tree varieties, you will need to look up the gender characteristics for each plant separately, since many of the qualities are different from plant to plant. The pistil and stamen can be a little difficult to identify. Look in the center of the plant where the petals meet in the middle and look for small lengths of stalk that are a different color than the petals. If they are tiny and thin, the stalks are probably pistils. If there are only 1-3 stalks and they’re kind of big, they’re likely stamens. You can only cross-pollinate flowering plants. Daisies, mints, sedges, peppers, and orchids can all be cross-pollinated. If the plant has a bud and a flower, it can be cross-pollinated! Many flowers have both male and female parts. In these cases, you do not need to worry about the genders of the plants. Some trees have male and female parts, and you do not need to worry about combining male and female varieties.

Clip off an unopened flower bud on the male plant. Find a portion of the plant that hasn’t bloomed yet. Use garden shears or scissors to clip the plant off under its stem. Carefully handle the unopened bud and transfer it to a stable work surface.Tip: Unopened buds will be bulbous and thicker than other portions of the plant. You can find them at the end of the stems on the plant. The location of the buds will differ from plant to plant.

Use tweezers to remove the sepals and petals from the bud. Sepals are the green leafy portions around the base of the bud. They protect the sensitive portion of the bud. Use tweezers to gently tear these portions away. Once you have access to the petals, peel them back and remove them to access the interior of the bud.

Brush the bud over a piece of paper or petri dish to collect the anthers. The anthers are the small seed-like particles that contain pollen. Set a piece of paper down and fold the edges up or hold the bud over a petri dish. Tilt the bud over the paper or dish and brush the top of the bud with your tweezers. You can use a cotton swab or paint brush if you’re worried about damaging the plant. Let the pollen particles and anthers drop to the paper or dish. If it’s windy outside, do this indoors. The more anthers you can collect, the greater the odds that the cross pollination is successful.

Dry the anthers overnight by storing them inside. You don’t really need to do anything to the anthers to dry them out, since the moisture will naturally dissipate over time. Leave your petri dish or glass jar uncovered and leave the container out in a dry area for at least 12 hours to dry them out. Transfer the anthers and pollen to an airtight, glass jar if you collected them on a sheet of paper. The paper simply makes it easier to collect a large number of anthers. Drying the anthers will increase the odds that your new plant pollinates correctly.

Remove the sepals and petals from a bud on the female plant. Find an unopened bud on the female plant that you’re cross-breeding with. Without removing the bud from the stem, peel off the sepals around the base of the bud. Peel back the petals, leaving them intact if you can. If you can’t, remove the petals as well. This is a really delicate process. Do your best to leave the stigmas, which are the filament in the middle of the bud, undisturbed while you do this. This process may not work if you damage the center of the plant.

Apply the anthers to the female plant using your finger or a paintbrush. Take the dried anthers and brush them over the center of the female bud. You can either dip your finger into the anthers and brush them on top, or use a clean, dry paintbrush to apply them to the plant. Add as many of the anthers as possible to increase the odds that the plant grows successfully. Be extremely delicate if you’re doing this by hand. You don’t want to knock off any portion of the interior bud.

Clip the new bud off after a few weeks of growth. The amount of time required for the hybrid bud to grow depends on the type of flowers that you’re cross-pollinating. Often, you will see a new bud develop over the course of 2-3 weeks. This new bud will likely look quite different than the other buds on the plant. Once the new bud has had some time to develop, clip it off with garden shears and scissors. Trim 2–3 inches (5.1–7.6 cm) under the stem and remove it. Determining when to clip the new bud can be kind of a trial and error process. You want to clip the bud off after new seeds have grown, but before the bud has a chance to develop juvenile traits.

Collect the hybrid seeds and store them in the refrigerator. Set your bud down over a piece of paper or petri dish. Use a small utility knife to cut halfway into the bud and gently tear it open. Inside, there are seeds. Locate the seeds in the membrane of the plant and remove them by hand or with tweezers. Store them in an airtight container along with some moist potting soil. Since you’re collecting your seeds after the plant has already started budding, you are unlikely to be successful if you plant the seeds right away. You have to wait for the next growing season to plant your hybrid plant.

Plant the new seeds in the spring, a few weeks before the growing season. When you’re ready to plant your seeds, remove them from the refrigerator and let them reach room temperature. Then, dig a 6–12 in (15–30 cm) hole in a fertile part of your garden, 1–4 feet (0.30–1.22 m) away from the mother plant. Plant your seeds the same way that you planted the mother plant. Since your new plant is an entirely new variety, it is hard to predict what kind of water, fertilizer, or soil the plant needs to thrive. In general, treat your new hybrid plant the same way you would treat the mother plant in terms of watering, fertilizer, and light. If the plant struggles to thrive, try cultivating it like the father plant. Some combination of the two methods will help you determine what works and what doesn’t. There is always some risk that the hybrid plant will not grow. It’s not always your fault, though. Some combinations will simply not work and it’s impossible to know ahead of time.

Grafting Plants Together

Select 2 plants with branches or stems of a similar size. Grafting is most effective with asexual, hardwood plants, so you don’t need to worry about finding mother and flower plants. Typically, grafting is most efficient in the early spring before either of the plants have had an opportunity to grow. Graft hardwood or asexual plants together in the early spring before the growing season begins. You may be able to graft some flowering plants together, but this process is generally less effective than cross pollination for flowering plants. So long as a plant has a firm stem though, it can be grafted to another plant. Apple, citrus, cherry, beech, and ash trees can all be grafted. Softer-stemmed plants that can be grafted include roses, tomatoes, eggplants, and boxwoods.

Remove a strong, healthy branch from one of the plants to make a scion. First, select a strong, healthy branch to remove from one of the plants. Sterilize your shears or gardening scissors by heating the blades under an open flame or soaking them in a sterilizing solution, like isopropyl alcohol. Use the garden shears or gardening scissors to trim off a 6–12 in (15–30 cm) length. Make sure that there are buds on the branch that you remove.Variation: Alternatively, you can cut the top half of the plant off from the trunk or main stem by cutting at a 45-degree angle. These larger grafts will be layered against the root plant, which is the half of the plant that is already planted, after making a 45-degree cut. Wrap the 2 cuts together and tie the branches tight. This process is harder to perform, but will generally yield strong results if done correctly. In grafting terms, this portion of the plant is known as the scion. The buds are the knotty, round bumps on the branch. It does not generally matter which plant you remove. If one of the plants grows much more quickly than the other, remove a branch from the plant that grows faster. You can make a scion out of the plant’s skin, wood, or bark. So long as it is the exterior portion of the branch, it does not matter what the origin of the organic matter is.

Clean a grafting knife and cut a 2–3 in (5.1–7.6 cm) strip out of the scion. Sterilize your grafting knife by holding the blade under an open flame or washing it in a sterilizing agent. Insert the edge of your blade into the skin of the branch or stem where there is at least 1 bud and dig 0.25–0.5 in (0.64–1.27 cm) into the skin. Rotate your blade all the way around the skin. Repeat this process 3–4 inches (7.6–10.2 cm) under the first cut and pry the skin off of the plant. Trim portions of the skin off to make a rectangular length of skin. A grafting knife is similar to a pocket knife, but it has a dull edge that makes prying the skin easier. You can do this with a pocket knife or utility knife if you’re careful. You only need a small portion of skin to successfully graft the plant. This will not work if there isn’t a bud on the skin that you remove.

Hold the scion up to the target plant and cut around it. Take your scion bark or skin and hold it up against the trunk or stem of the plant, anywhere near the bottom third of the plant. Use a sterilized grafting knife to cut into the target plant by dragging the blade around the scion. Once you’ve cut guidelines into the target plant, set your scion aside. You don’t need to be precise. So long as the scion will fit in the opening that you make on the target plant, this will work.

Peel off the skin on the surface of the target plant. Peel away the surface material of the target plant where you made your incisions. Dig the blade into the skin and carefully peel the surface off. Remove enough skin, wood, or bark so that your scion can sit flush against the target plant.

Put the scion on the target plant and wrap it with vinyl tape and aluminum foil. Hold the scion over the area that you removed on the target plant. Press it into place and wrap the scion against the stem or trunk using vinyl tape. Pull the tape as tightly as possible to ensure that the scion doesn’t move as it binds to the target plant. Cut the excess tape off and wrap the entire portion in aluminum foil. Add a few more layers of tape to protect the graft. The aluminum foil will prevent moisture from escaping while keeping sunlight out, which can cause the target plant to reject the graft.

Remove the wrapping after 3-4 weeks. After 3-4 weeks have passed, the graft will have healed and the target plant will either have accepted or rejected the graft. Remove the aluminum foil. Carefully peel away the vinyl tape. Do this as gently as possible to ensure that you don’t rip the scion off of the plant. If the graft falls off right way or it looks dead, the graft did not take and you will need to try again.

Cut the top half of the plant off using shears or pruning saw. The graft will not grow if the leafy, healthy portion of the plant above it is hogging all of the resources. To ensure that the graft receives plenty of nutrients and begins growing, cut the top half of the plant off. Use garden shears for smaller plants and a pruning saw for juvenile trees and stronger plants. Prune any healthy leafy areas near the graft to remove them. Cut a few notches 3–4 inches (7.6–10.2 cm) above the graft to wound the plant. The plant will send more resources to this area to help it heal, which will increase the odds that the graft grows. A pruning saw is basically a large knife with a serrated edge. It is designed for pruning tougher vegetation.

Wait for the graft to grow and tie it to the target plant. It may take several weeks for the graft to grow. In extreme cases, it may be an entire year before the buds on the graft grow. Care for the plant the same way you would care for the target plant in terms of water, pruning, and fertilizer. Once the graft grows 8–16 inches (20–41 cm) in length, use twine to tie it to the remaining portion of the trunk or stem. This will ensure that it grows evenly and straight as it develops. This new plant is an entirely new species! Over time, it will overtake the target plant’s stem and completely incorporate the old root system into the new plant.