Will Different Types of Squash Cross Pollinate?

Squash Types

• Summer squash, pumpkins, gourds and some types of winter squash that are botanically members of the same species -- Cucurbita pepo -- will cross-pollinate. Various common or colloquial names exist for the plants of this species. For example, summer squashes are also referrred to as zucchinis or Italian marrows, or further referred to as straightneck, crookneck or scallop squash. Some of the winter squashes, especially those that develop orange skin, are quickly described as being pumpkins.

Cucurbita Moschata

• Confusingly for the gardener, some varieties of plants in the species Cucurbita moschata are also known by common names such as pumpkin, acorn or butternut squash, gourd or trumpet zucchini. Any variety of this species will also potentially cross-pollinate with plants in the same species group. This can be complicated to follow, as so many plants in Cucurbita moschata and Cucurbita pepo are interchangeably referred to as types of squash and pumpkin. Again, only plants in the same species cross-pollinate, and unfortunately for gardeners, not all plant seed packets reveal the species identity of the variety.

About Pollination

• All plants in the genus Cucurbita produce yellow flowers that are either male or female in gender based on the presence of male stamens or a female pistil and ovary. Only pollinated and fertilized female blossoms yield fruits. Honeybees facilitate most of the pollination of squash plants in the home garden. Multiple visits are required on these blossoms that remain open only one day. Cucumber and melon pollen does not affect pollination of any summer or winter squash vine, so bees loaded with that form of pollen do not affect the fruit set on the squash plants at all.

Insight

• Unless you wish to save the seeds of your squash, do not worry if various winter and summer squash plants grow in your vegetable garden patch. While pollen from different squash types result in fruits on other intra-species varieties, it does not result in a mutant, strangely tasting fruit. Only the seeds in the fruit carry the hybrid genes from the two plant parents. If these hybrid seeds are sown the next year, a plant will emerge that produces a variable fruit with characteristics that are intermediate of the two plants that supplied the pistil and the pollen.